Nine years after the failure of the original Discovery mission to Jupiter in "2001," Dr. Heywood Floyd (Roy Scheider) finds out from the USSR that the abandoned ship is falling towards Jupiter's moon Io and the critical data from the mission will be lost. He convinces the U. S. government that despite a diplomatic crisis brewing between the two countries, he must get to the ship and recover the data. The Soviets allow him to go, along with Dr. Walter Curnow (John Lithgow), the chief designer of Discovery, and Dr. R. Chandra, who was the chief designer of HAL 9000. Onboard a USSR spacecraft led by Tanya Kirbuk (Helen Mirren) heading to the still-orbiting giant Monolith where Discovery still remains, they all struggle to find out what the Monolith's purpose is, and what happened to the final crewmember of the US vessel, David Bowman (Kier Duella), whose cryptic message was the last transmission recieved from Discovery.