A teenage heart transplant patient is rushed to the hospital when she has an allergic reaction while living in a "clean" room, and House and Wilson work out the kinks of their new living arrangement.
Rare zoo animals are being abducted and impregnated in a case that Mulder believes may be linked to an alien conspiracy.
Sipowicz and Clark continue tracking down leads as they attempt to solve a rape-homicide case that sent an innocent man to prison for eighteen years; and Medavoy and Jones try to link the murder of a churchgoer to the victim’s wife having an affair.
During the 1972 presidential campaign, Mike Detweiller comes to McKinley high to represent Senator George McGovern.
Jake helps Major Beck prepare for a special visitor from the Cheyenne government, while Hawkins continues to work with Chavez to uncover the secrets of this new regime.