Titan is the most Earth-like satellite body in our solar system. With not so extreme temperatures as other planets and satellites as well as the only large liquid-bodies, Titan is the best choice for "probability". Also, it is within our solar system so it does not appear to need extremely super-advanced technologies and is much easier to believe.
After a member of a geological research team who was sent to Saturn's largest moon: Titan crashes their spacecraft into a space station, another team is sent to Titan to investigate, not knowing the terror that awaits them.
