The Clashing Gates

A boarding battle between rocks that hate ships.

Style: Kinetic trireme gauntlet for 6 level-8 PCs, mixing helm checks, boarding fights, and hard navigation choices.
Win: Thread the Symplegades with the ship intact enough to sail and the Titan-kin boarding rite broken.
Lose: The rocks learn the ship's name, crush the route shut, and leave survivors stranded on living stone.
Maguffin: Bronze Dove of Phineus · Ally: Kyane the Blue Oar · QG: Captain Philon of the Mist Trireme

"Send the dove first, count the heartbeat second, and trust the oar that pulls when the stones inhale."

Major Beats

Philon's confidence cracks when the rocks answer the trireme's old name.
The first omen is useful but not complete.
Boarders attack the ship's timing more than its crew.
The finale rewards choosing exactly when to fight and when to row.

Difficulty

Tier	Adjust
As Written ★	6 PCs · APL 8
Library Standard	6 PCs · APL 8 — Identical to As Written — this guide’s baseline is already 6 PCs at average level 8.
Easier	APL 4–6: reduce minion counts ~30%; DCs −2; boss loses one recharge or legendary option.
Harder	APL 10–12: boss HP +25–35%; +1 legendary action; add a lieutenant or extra wave.

ENC 1 — Dove Before Oars

Skill / Medium · ~45 min · Trireme deck, fog lane, left and right rock faces, current arrows, and three ship zones.

Navigation challenge: 5 successes before 3 failures at DC 15 using vehicles, Athletics, Perception, or Survival.
The Bronze Dove grants advantage and tells which rock will move first.
Recruit Kyane by honoring her cadence; she grants one ship-check reroll per later encounter.
Failure damages a ship zone or starts Encounter 2 with Rock-Grapplers already aboard.

ENC 2 — Boarders From Both Stones

Medium · ~55 min · Main deck with mast, two boarding bridges, stern helm, damaged oar banks, and rail hazards.

At initiative 20, choose: rocks close 20 ft, a ship zone takes damage, or two raiders board.
Non-combat option: beat the Tide-Ogre's cadence with Performance/Athletics DC 16 to stall one bridge.
Repairing an oar bank takes an action and tools or Strength DC 15; Kyane makes it a bonus action once.
The Bronze Dove can identify the Stone Scion sustaining the anchor chant.

ENC 3 — The Count Between Clashes

Hard · ~70 min · Narrowing channel, sliding deck markers, exposed ram, anchor-chain to right rock, and stern escape wake.

Seven-count clock: each round PCs assign helm, oars, repairs, and boarder control before the rocks move.
Spend the Bronze Dove to cancel one rock-clash or reveal the anchor-chain's weak link.
Win by cutting the anchor-chain and clearing the gap, forcing Brontes overboard, or bargaining with his honor.
If the ship reaches 3 broken zones, it still escapes only if PCs jettison cargo or beach on a living rock.

STAT BLOCKS

Kyane - AC 16/HP 83 - ship check reroll
Rock-Grappler Raider - AC 16/HP 74 - rail-pull hook
Tide-Ogre Bosun - AC 15/HP 118 - deck-damaging maul
Stone Scion - AC 17/HP 132 - anchor chant controller
Brontes Gate-Heir - AC 18/HP 210 - titan hammer boss

Maguffin

Bronze Dove of Phineus

Launch it to scout currents, granting advantage on one vehicle (water) or Perception check.
Its wingbeat names the safe count; spend it to cancel one rock-clash or expose the Titan-kin anchor.

NPC / ALLY

Captain Philon of the Mist Trireme

He must prove a safe western route before the fleet commits to the passage.
He will sacrifice cargo before crew, but not the ship's dove unless convinced it saves everyone.

Kyane the Blue Oar

Recruit Enc. 1: Let her call cadence during the first crush, or beat her honest in a rowing contest.
AC 16 · HP 83 · Oar-staff +7 to hit, 14 bludgeoning; grants one reroll on a failed ship check.

Remember

Thread the Symplegades with the ship intact enough to sail and the Titan-kin boarding rite broken.

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