The Isle of Stonegaze

One-Shot · ~6 Players · Average Level 8 · Greek Mythology · ~3–3.5 hrs / 3 Encounters

Style: Mythic Quest — Ship Combat / Marsh Skirmish / Cave Boss | Win Condition: Defeat Euryale (0 HP or pool self-petrify ×2) and retrieve the Eye of Medusa | Setting: Open sea aboard Ariadne's Thread → rocky shore → Mireweed Marsh → temple ruins → Cave of Euryale.

Scholarly merchant Theron of Corinth hires the party to recover the Eye from the Isle of Stonegaze. Midvoyage, harpies and compelled merfolk assault the trireme. On the island, survivors Pyrrha and Old Lysander guide the party through a cursed saltmarsh (recruit Maren), then into the cave of Euryale, the Stone Queen.

"Where serpents crown the stone queen, let her own gaze be her ruin — the still pool sees what mortal eyes dare not." — The Scroll of Theron (22-word handout; payoff = Still Pool in Enc. 3). Don't explain it — let players puzzle it out. Lysander confirms if shown (DC 13 Insight).

Major Beats

Tavern briefing — Theron hires the party; Scroll of Theron handoff.
3-day voyage (optional sea RP) aboard Ariadne's Thread under Captain Kleon.
Enc. 1 — Harpies Over the Ariadne's Thread: protect sails; free/recruit merfolk; Long vs Short Rest outcome.
Beach landing; meet Pyrrha (guide) and Old Lysander (scroll interpreter + Blindfolds).
Enc. 2 — Mireweed Marsh: lizardfolk patrol; recruit Maren for fire support.
Temple ruins (no combat) — scavenge Polished Bronze Mirror, Blindfolds, Stonechill vials.
Enc. 3 — Cave of Euryale: Lamia + Medusa Sentinel; Euryale enters round 3; Still Pool / mirror win path.
Retrieve Eye of Medusa; return to Theron (optional moral / epilogue hook).

Creature / Enemy List

Creature	Easy	Med	Hard	Notes
Harpy	2	3	4	Enc. 1; Matriarch on Deadly
Corrupted Merfolk	3	4	5	Enc. 1; freeable / recruitable
Lizardfolk Warrior	3	4	4	Enc. 2 (Deadly: 5)
Lizardfolk Shaman	1	1	1	Enc. 2
Lamia	2*	2	1	Enc. 3 (*Easy: Lamias only, no Medusa)
Medusa Sentinel	0	1	1	Enc. 3 (Deadly: 2)
Euryale (Boss)	1 (adj.)	1	1	HP 100 / 140 / 168; Deadly 220
Maren	—			Recruitable ally Enc. 2 → Enc. 3

Difficulty Scaling — Session Overview

Encounter	Easy (APL 4)	Medium (APL 6)	Hard (APL 8 ★)
1 — Ship	2 Harpies, 3 Merfolk; sail HP 10; Song DC 9; harpies ignore sails until rd 3	3 Harpies, 4 Merfolk; sail HP 12; Song DC 11	4 Harpies, 5 Merfolk; full mechanics as written
2 — Marsh	3 Warriors, Shaman HP 38 (2nd-lvl only); Maren helps mid-fight	4 Warriors, 1 Shaman; Maren post-combat only	Baseline + Fire Flasks / Enc. 3 support on recruit
3 — Cave	2 Lamias only; no lair; Euryale HP 100, Gaze DC 13, enters rd 4	2 Lamias + Medusa; 1 LA/rd; HP 140, Gaze DC 15	1 Lamia + Medusa; full Euryale (168 HP, 3 LA, Gaze DC 17)

Deadly (APL 10): Enc.1 adds Harpy Matriarch (+2 atk/saves, HP 60, Song DC 13, 500 ft) + wave of 3 merfolk rd 4. Enc.2: 5 Warriors, Shaman 4th-lvl wall of fire, pre-cast Spike Growth. Enc.3: 3 Lamias + 2 Medusas; murky pool (clear: action, DC 14 Ath/Inv); toxic statue dust; Euryale HP 220, 4 LA, enters rd 2.

Encounter 1 — Harpies Over the Ariadne's Thread

Medium · 45–60 min · 5–7 rounds | Terrain: Trireme deck 80×25 ft + sea surrounds

4× Harpies dive on sails while 5× Corrupted Merfolk board from both sides. Win: drive off/kill all harpies + defeat or free all merfolk.

Primary goal: protect 3 sail sections (each AC 11 / HP 15). Harpies prioritize sails unless a PC is in melee reach.
≥1 sail survives → Long Rest before Enc. 2. All 3 destroyed → row to shore, Short Rest only.
Luring Song (DC 11 WIS): targets crew first; charmed crew block movement. Snap out: Action, DC 12 CHA/Persuasion or DC 12 STR drag.
Free merfolk (Action, adjacent): DC 15 Arcana / Insight / Religion → friendly ally. Recruit up to 3 to guard ship: DC 14 Persuasion.
Kleon (init 5): spear +4 (1d6+1) or lash rope — Athletics DC 12, restore 10 HP to one sail.
Overboard: full move + Athletics DC 13 to climb back. Merfolk knocked off retreat.

Resolution: Harpies gone + merfolk defeated/freed. Freed merfolk stop fighting automatically.

Encounter 2 — Mireweed Marsh

Medium · 50–60 min · 4–6 rounds | Terrain: Boggy marsh + ruined hut, 100×80 ft

After shore RP with Pyrrha/Lysander: 4× Lizardfolk Warriors + 1× Shaman attack on sight. Maren shelters behind her hut — recruitable. Win: defeat all lizardfolk; proceed to temple ruins.

Approach: Perception DC 12 → spot bogs/bridge early → advantage on initiative if ambushing.
Maren ID: Insight/Perception DC 12 (else she shouts on rd 2). Adjacent before fight ends → she Fog Clouds the Shaman (breaks concentration).
Recruit (post-combat): Persuasion DC 13; Nature/Arcana DC 10 = adv; mention Lysander's "marsh woman" → DC 8; sincere marsh-protection vow = auto.
Terrain: 4× bog patches (15×15, DT for non-lizardfolk); 3× mangroves (½ cover, climb Ath DC 12); log bridge (Acro DC 12; fall = −15 ft move to exit); hut = ¾ cover.
Tactics: Shaman opens Spike Growth on bridge/approach → Call Lightning; Warriors Bite+Javelin, Clamping Jaws OA (grapple, escape STR DC 13). Swamp Stride ignores shallow water DT.
Recruit rewards: 3× Fire Flask; Enc. 3 ally (init 8: Flaming Sphere, Heat Metal, Cure Wounds); lore that fire breaks lamia concentration.

Resolution: Lizardfolk defeated → temple ruins scavenge (Mirror, Blindfolds, Stonechill vials) → cave descent.

Encounter 3 — The Cave of Euryale (Boss)

Hard · 60–75 min · 8–12 rounds | Terrain: Cave shrine 90×70 ft + 30 ft inner chamber

Petrified statues fill a green-brazier cave; Still Pool glows center. Baseline: 1× Lamia + 1× Medusa Sentinel; Euryale enters rd 3. Optional: Maren. Win: Euryale to 0 HP or pool self-gaze fail twice (fully petrified) → take Eye amulet.

Still Pool (15×10 ft): reflection → adv on Petrifying Gaze saves. If Euryale ≤30 ft + LoS to pool: start of turn CON DC 17 vs own gaze (overrides petrified immunity). Fail → restrained; 2nd consecutive fail → petrified.
Force her to the pool: Deception/Persuasion DC 15, or Mirror BA Reflexion Sleight of Hand DC 14. She avoids via Legendary Move.
Statues: 8–10 × ½ cover (AC 13 / HP 20). Shatter → 5 ft DT + DEX DC 12 or 2d6 bludgeoning. Lamias may shatter near PCs.
Entrance (init 20, rd 3): Euryale observes first turn (Serpent Strike only — no Gaze). Full Gaze from rd 4. Lair actions from rd 3.
Lair (init 20): Serpent Surge (5 ft of wall, DEX DC 14, 2d6 pierce); Stone Dust Cloud (20 ft obscure); Cave Tremor (10×10 becomes DT).
Minion tactics: Lamia — Intoxicating Touch on casters; Suggestion DC 13 WIS away from pool. Medusa — ranged Gaze aura; melee only if cornered. Maren — Flaming Sphere / Heat Metal / Cure Wounds.

Failure: TPK / full petrification without pool win — Eye remains with Euryale; Theron's quest fails.

Resolution: 0 HP or pool-petrify → retrieve Eye of Medusa (dark gem, gold amulet, faint purple glow). Powers unclear until Theron — epilogue hook on his true motives.

Creature Stat Blocks

Harpy

Medium Monstrosity, CE · CR 1 (200 XP)

AC 11 | HP 38 (7d8+7) | Speed 20 ft., fly 40 ft.

STR 12 DEX 13 CON 12 INT 7 WIS 10 CHA 13 · PP 10 · Common

Multiattack. 2× Claws +3 (6, 2d4+1 slash).

Luring Song. 300 ft: DC 11 WIS or charmed (incapacitated, must approach). BA each turn to continue. Re-save end of turn; ends if harpy incapacitated / out of range.

Corrupted Merfolk

Medium Humanoid (Merfolk), N (Compelled) · CR 1/4 (50 XP)

AC 11 | HP 22 (4d8+4) | Speed 10 ft., swim 40 ft.

STR/DEX 13 CON 12 INT/WIS 11 CHA 12 · Perc +2 · Amphibious · Aquan, Common

Spear. +3, 5 ft or 20/60: 4 (1d6+1) / 5 (1d8+1) two-hand.

Free (Action, adj.): DC 15 Arcana/Insight/Religion → friendly. Guard ship: DC 14 Persuasion (≤3).

Lizardfolk Warrior

Medium Humanoid (Lizardfolk), N · CR 2 (450 XP)

AC 16 | HP 45 | Speed 30 ft., swim 30 ft.

STR 16(+3) DEX 10 CON 15 INT 7 WIS 12 CHA 7 · Perc +3, Stealth +4, Survival +5

Hold Breath 15 min. Swamp Stride: shallow water ≤3 ft not DT.

Multiattack. Bite +5 (1d6+3) + Javelin +5 (1d6+3, 30/120). Reaction Clamping Jaws: OA hit → grappled (escape STR DC 13).

Lizardfolk Shaman

Medium Humanoid (Lizardfolk), N · CR 4 (1,100 XP)

AC 13 | HP 52 | Speed 30 ft., swim 30 ft.

STR 14 DEX 10 CON 14 INT 12 WIS 16(+3) CHA 8 · Nature +4, Perc +6

Spellcasting WIS, DC 14, +6. Cantrips: poison spray, produce flame. 1st: fog cloud†, healing word, thunderwave. 2nd: spike growth†, hold person†. 3rd: call lightning†, conjure animals†.

Bite. +4 (1d6+2 pierce).

Lamia

Large Monstrosity, CE · CR 4 (1,100 XP)

AC 13 | HP 97 (13d10+26) | Speed 30 ft.

STR 16 DEX 13 CON 15 INT 14 WIS 15 CHA 16 · Dec +7, Ins +4, Stealth +3 · DV 60

Innate (CHA DC 13, +5): at will disguise self, major image; 3/day charm person, mirror image, suggestion; 1/day geas.

Multiattack. Claws +5 (14, 2d10+3) + Dagger +5 (5, 1d4+3); may replace either with Intoxicating Touch +5 — 1 hr: disadv WIS checks/saves; can't concentrate.

Medusa Sentinel

Medium Monstrosity, LE · CR 6 (2,300 XP)

AC 15 | HP 127 (17d8+51) | Speed 30 ft.

STR 10 DEX 15 CON 16 INT 12 WIS 13 CHA 15 · Dec +5, Ins/Perc +4, Stealth +5 · DV 60

Petrifying Gaze. Start turn ≤30 ft seeing eyes: CON DC 14. Fail → restrained; next fail → petrified; success ends. Avert: no save, disadv attacks vs her.

Multiattack. Snake Hair +5 (4 + 14 poison; CON DC 14 or poisoned 1 hr) + 2× Shortsword +5 (5, 1d6+2).

Euryale, the Stone Queen — BOSS

Large Monstrosity (Gorgon), LE · CR 12 (8,400 XP)

AC 17 | HP 168 (26d10+26) | Speed 30 ft.

STR 12 DEX 16(+3) CON 14 INT 16 WIS 15 CHA 20(+5) · Saves DEX+7 CON+6 WIS+6 CHA+9

Skills Dec+9 Ins/Perc+6 Stealth+7 · Resist Poison · Immune Petrified (except own reflection) · DV 120, Truesight 30

Petrifying Gaze (aura). Start of her turn: each ≤30 ft seeing eyes CON DC 17. Fail by 5+ = instant petrify; fail = restrained (next fail = petrified). Avert = disadv attacks.

Mirror / Pool Vulnerability. Sees own reflection ≤30 ft (bright light / Still Pool LoS) → CON DC 17 vs own gaze (overrides immunity).

Multiattack. Snake Hair +7 (16 poison; CON DC 16 or poisoned 1 hr) + 2× Longsword +5 (10/11), or Focused Gaze (CON DC 17 disadv) + 2× Longsword.

Legendary 3/rd: Move (½ speed, no OA); Serpent Strike (1); Unleash Gaze (2) — force Gaze save. Lair: see Enc. 3.

Key Items & McGuffins

📜 The Scroll of Theron

Handout · Given at tavern · 22 words

"Where serpents crown the stone queen, let her own gaze be her ruin — the still pool sees what mortal eyes dare not."

DM: Don't explain. Still Pool is the payoff. Lysander confirms if shown (DC 13 Insight to notice his reaction).

◈ Eye of Medusa

Session McGuffin · Worn as amulet on Euryale

Dark gem in golden setting; faint purple glow. Retrieved when Euryale is slain or pool-petrified.

Powers unclear until Theron evaluates — epilogue hook (he wants it to restore petrified daughter Callista).

🪞 Polished Bronze Mirror

Wondrous · Common · 1 hand · Temple ruins (collapsed altar)

Indirect Viewing: observe without LoS exposure to gaze. Gaze Deflection: viewing via reflection → adv on gaze saves.

Reflection (BA): angle toward medusa ≤30 ft of Still Pool — Sleight of Hand DC 14 → she saves vs own gaze. Pyrrha can point here (DC 14 Persuasion).

Blindfold of Apollo ×3

Wondrous · Common · From Lysander

While worn: Blinded, but Blindsight 15 ft + immune to gaze effects. Remove = BA. Lysander gives freely if party will enter the cave.

🔥 Fire Flask ×3

Improvised · From Maren on recruit

Action: throw 20 ft (+PB Dex) → 2d6 fire. BA: throw 10 ft → hit 2d6 / miss 1d6 splash. Sticky marsh-pitch flame; good vs lamia concentration.

Still Pool / Stonechill

Environmental · Enc. 3 center · 15×10 ft

Reflection = adv vs gaze. Gaze creature ≤30 ft + LoS → own-gaze save each turn start. Euryale avoids with Legendary Move.

Stonechill Water vials (urn near cave steps, per Pyrrha): Lysander once carried pool water out — flavor/loot; no separate combat stats.

NPC Quick Reference

Theron of Corinth

Questgiver · Neutral (suspected) · Tavern

Look: lean 50s, ink-stained fingers, merchant dress / scholar bearing.

Surface: wants Eye for academic study (reveals truths / pierces illusions).

Secret: daughter Callista petrified on a past expedition he funded — believes Eye can restore her. Won't volunteer this.

DC 14 Insight: hiding danger. DC 16 Persuasion / DC 13 Intimidation: admits "personal connection." DC 18 Investigation (notes): sketch + name Callista.

Kleon, Captain

Trireme Captain · LN · Enc. 1 helper

AC 13 | HP 45 | Speed 30 · STR 15 DEX 13 CON 14

Role: init 5 — spear +4 (1d6+2) or sail repair Athletics DC 12 (+10 HP to one sail).

RP: gruff, pragmatic, respects competence; no drama.

Pyrrha

Island Survivor · NG · Shore guide

Look: mid-30s, lean, scarred arm (lamia claws). Desperately wants off-island.

Knows: safe marsh route; Mirror (collapsed altar); Stonechill vials (urn by cave steps); "pool that glows like moonlight."

DC 12 Persuasion / rescue promise → guides marsh. DC 14 → item locations + lizardfolk timing (adv init Enc. 2).

Old Lysander

Blind Priest of Apollo · NG · Shore hermit

Look: ancient, milk-white eyes (lost sight glimpsing Euryale in the pool 20 yrs ago). Apollo pendant, sun-ray staff.

Gives: Blindfolds of Apollo; confirms scroll; cave layout from memory.

Line (scroll shown): "The pool is the secret. She will not look at it willingly. But you can make her look." — "Because I looked into it myself. And it showed me her."

Maren, the Marsh-keeper

Druid Hermit · NG · Recruitable Enc. 2 → Enc. 3 ally

Look: 40s, marsh-stained robes, reed-charm staff. Grateful but wary; hates the curse on her wetland.

Recruit: Persuasion DC 13 (Nature/Arcana DC 10 = adv; "marsh woman" = DC 8; vow = auto). Mid-fight: Fog Cloud on Shaman if adjacent.

Provides: 3× Fire Flask; Enc. 3 init 8 — Flaming Sphere (2d6 fire/turn), Heat Metal, Cure Wounds; fire lore vs Stone Queen guardians.

Aftermath / Hooks

Return Eye to Theron — he may finally admit Callista's fate; moral choice whether to trust him with it.

Pyrrha / Lysander / Maren may want passage off-island. Freed merfolk (if any) guard the ship during Enc. 2–3.

Petrified statues in the cave = prior adventurers/sailors — some may be restorable with greater restoration (DM discretion).