Dopplegänger is a single person, interactive fiction, text adventure. Inter-Planetary Human Simulations has finally developed an android, the "IPHS-3939/41-B" called "IP-39" for short, that is "the ultimate human match." This amazingly humanoid machine is now missing. Was it stolen? Did it escape? Most importantly, where is it now? The player takes the role of Michael Telan, a secret agent working for Argrath Intelligence. It is your task to investigate and recover the IP-39.