The freeware horror-themed point-and-click adventure 5 Days a Stranger is the first part of the The Chzo mythos. It tells the story of a cat burglar named Trilby who sets out to steal the family valuables from the manor of the recently deceased Sir Roderick DeFoe. But once Trilby gets inside, all the doors and windows are locked, and he cannot get out.

Soon he realizes that four other people are trapped in the house as well and the house has a reason for keeping them there - a truly sinister one. Together with scavenger Philip Harty, TV reporter Simone Taylor, the youngster Jim, and the secretive AJ, Trilby has to delve into the family history to solve the secret the manor is hiding.

The game is controlled through five mouse-controlled actions: walk, look, use, and talk. These can be selected from the bottom of the interface, from the inventory screen, or by cycling through them with the space bar. The entire game takes place over the course of five days, introducing a whodunnit theme when some characters go missing. Most puzzles are inventory-based, but some also rely on conversations. It is also possible to die during certain sequences if the player does not react quickly.