The game takes place in the mansion of the Edison family: Dr. Fred, Nurse Edna, and their son Weird Ed. Living with the Edisons are two large, disembodied tentacles – one purple and the other green. The player starts out by selecting two of six characters to accompany protagonist Dave Miller. The intro sequence shows that a meteor crashed near the mansion 20 years earlier. The sentient meteor took control of the family and caused Dr. Fred to begin conducting human experiments while plotting to take over the world. After the introduction, Dave and his two companions prepare to enter the mansion to rescue his cheerleader girlfriend, Sandy Pantz, whom Dr. Fred has kidnapped.