The Enterprise encounters the emergency signal of a Daedalus class ship which disappeared in the area 200 years earlier. Although the signal leads to an uninhabited moon, Troi is convinced that there is someone still alive. Due to a magnetic storm on the moon, the Enterprise is unable to use the transporters so Riker, Troi and Data attempt to use a shuttlecraft to land on the moon on a rescue mission but, the craft is destroyed by the storm. They are joined by O'Brien who has found a way to use the transporter for a single beaming and to rig up a booster so they may be rescued by the transporters. As they are about to beam up, the storm lets loose a lightning bolt which knocks the crew unconscious. Riker manages to come to long enough to activate the booster and they are all returned to the ship. Shortly after their return, Data, Troi, and O'Brien begin to behave strangely and they attempt to take over the ship. When their attempted mutiny fails, they run for ten-forward where they take hostage Keiko, Worf and other crew members. Picard must find a way to free the hostages, and discover why Data, Troi and O'Brien have attempted to take over the ship.
