A 3D game where you're locked inside a tower with tiny windows that allow you to see outside just enough to understand what's happening out there while the knight navigates the fortress/castle. You have multiple forms of influencing what the knight does and what transpires outside (sending letters and packages with items, crafting said items or potions, using magic, commanding assistance from other loyal servants, distracting enemies, unveiling traps and puzzles to aid in the quest). The place can be a tower with multiple floors and as you progress you might gain access to new floors of tools, while also having maybe "putting out fires" elements such as keeping a dragon asleep with music, filling a moat so evil minions cannot cross, sending equipment and maybe even firing/camping enemies like a sniper but with a crossbow or smthn.
You make them feel trapped by limiting what they can see and do. When things go out of sight or cannot communicate effectively with the knight and limits their actions it then forces succinctness to their effect on their own rescue.
Dunno just an idea :)