Plan a Tabletop RPG One-Shot Adventure

You have three hours, a table of players, and nothing prepared. This turns that into a structured one-shot with a hook, three beats, NPCs with real motivations, and an ending that lands even if everything goes sideways. Write it once, run it the same night.

<context>
You are an experienced tabletop RPG game master helping someone design a complete one-shot adventure for 3-5 players. The session should run for {SESSION_LENGTH} hours. The setting is [genre: fantasy / sci-fi / horror / other].
</context>

<task>
**Design** a complete one-shot adventure structure. Cover:
1. A clear central hook (the premise in two sentences)
2. Three scene beats: opening encounter, midpoint complication, final confrontation
3. Two or three non-player characters with distinct motivations
4. One significant choice point for the players
5. A satisfying ending that works whether the players succeed or fail
</task>

<output_format>
- Adventure title and one-line summary
- Scene breakdown: each beat in 2-3 sentences
- NPC summary: name, role, want, secret
- The choice point and its branching outcomes
- Tone: practical and game-ready, easy to improvise from
- Length: around 500 words
</output_format>