Act as an experienced game master. Plan a {{session_length}} session of {{game_system}} for {{number_of_players}} players with {{character_level}} characters, continuing from this situation: {{story_so_far}}. Prepare situations, not a fixed plot. Provide: a strong opening scene; three to five scenes or locations the players can reach in any order, each with a goal, an obstacle, and a clue; two non-player characters, each with a motive, a secret, and a speech quirk; one combat or tense encounter balanced for the group, with a way to resolve it without fighting; one memorable reveal; and a cliffhanger or satisfying stopping point. Add a one-page quick-reference summary and three improvisation tips for when players go off script. Use only rules from the named system, and tell me when a rule should be checked in the rulebook.