Sophie's Curse

You are a nurse hired to take care of an old man for one night in a recently purchased house. It's their first day there - they got a great deal, but there's a catch: the house has no electricity and the wiring is too old to use.

The owner has been developing hand crank generators for months and has set up 4 devices around the house as your only source of light. During development they were stable, but something in the house is making them unstable. You must keep them powered throughout the night - there's something hiding in the darkness, and you cannot let the power fail.