Power Play (Star Trek: The Next Generation)

Plot

The USS Enterprise approaches Mab-Bu VI, from where it has detected a distress call. Commander Data discovers that the distress call is standard for Daedalus-class starships, which went out of service 172 years ago. He then finds that the USS Essex, a Daedalus-class ship, was lost in the region 200 years ago. After concluding that assessing the situation from the ship is inadequate, Picard decides that an away team must visit the moon. Troi indicates that she "feels" a living presence on the surface. Data announces that electromagnetic interference from electrical storms precludes the use of the transporter to the moon; Picard authorizes a shuttlecraft mission, manned by Riker, Data, and Troi.

As the shuttlecraft travels towards the moon's surface, the crew loses control, and Data makes a crash landing. By the time the shuttle lands, all communication with the Enterprise has been cut off by electromagnetic interference.

Riker suspects he has a broken arm due to the crash landing, and the three crewmembers emerge from the shuttlecraft to learn about their surroundings. They observe the front of a massive electrical storm, and Riker comments that it appears nothing like the front of any other electrical storm he has seen before. A tricorder scan indicates EM bursts across the entire spectrum.

Back on the Enterprise, the crew discuss rescuing the crew of the shuttle. Ro Laren states she can use the descent angle of the shuttlecraft to approximate the landing site. Miles O’Brien proposes that he should transport to the surface and use a pattern-enhancing device to allow a reliable transport of the away team. Geordi cautions Picard that O’Brien's chance of surviving the transport is about "fifty-fifty." O’Brien acknowledges the risk, and Picard grants permission.

O’Brien safely transports to Mab-Bu VI, and he is greeted with relief by Riker. As O’Brien prepares the transport procedure, the crew is struck by what appear to be bolts of electricity. All but Riker are incapacitated, and he hastens to begin the transport. Just before the four are transported, however, three light sources enter the bodies of Data, Troi, and O’Brien.

Upon their return to the Enterprise, Data, Troi, and O’Brien insist that the Enterprise conduct a survey of the southern polar region of the moon. The rest of the crew refuse. The three then stage a violent uprising and take command of the ship. They use hostages as leverage to force Picard to change course. Dr. Crusher determines that Riker was not affected because the pain from his broken arm repelled whatever force possessed the others. Troi, the leader of the mutineers, then reveals that she is the captain of the Essex. She claims that their spirits were trapped in the electromagnetic fields of the moon, and if the Enterprise transports their bones back to Earth, they can be set free. However, Picard is skeptical of her claim because of their violent actions.

La Forge, Crusher, and Ro devise a plan to separate the possessive entities from the crew members' bodies by inducing pain, then containing them by flooding the area with a particle field. However the plan fails when Data suddenly moves out of the attack area.

After Data threatens to kill everyone in the room, Picard agrees to comply with their demands. He tells Riker to let Data, Troi, and O'Brien move safely to one of the cargo bays. Picard, Worf, and Keiko O'Brien accompany them as hostages.

After they arrive, Picard challenges Troi about her claim to be captain of the Essex, and she reveals that the moon is a penal colony. O'Brien uses the transporter to beam hundreds of other prisoner entities into the cargo bay. These prisoners are to take over additional crew members' bodies so they can commandeer the Enterprise and return to their home planet.

The bridge crew activates the particle field, which sequesters the other prisoners. They then prepare to blow the cargo bay hatch, which would kill the six crew members in addition to all the prisoners. Picard, Worf, and Keiko each declare that they're willing to die, which forces the three prisoners to relinquish their hosts. Worf beams all prisoners back to the moon.

Data apologizes to Worf for the way he acted when possessed by a prisoner, adding that Worf must have exercised extreme self-control to not just smash Data to scrap. Worf says "You have no idea!"