The Alternative Factor

Did You Know?

• John Drew Barrymore was cast as Lazarus, but failed to show up for filming, without explanation; the part was quickly recast with Robert Brown.
• The producers filed a grievance with the Screen Actors Guild, which suspended Barrymore's membership for six months, preventing him from working as an actor during that time.
• The special effects for the extra-dimensional "winking" episodes were achieved by superimposing a moving photograph of the Trifid Nebula over the action.

Plot

The Enterprise shudders from a sudden energy pulse. Spock tells Kirk that the planet’s gravity dropped to zero and the surrounding space briefly vanished from existence. Sensors detect a human on the planet who wasn’t there before. Kirk and Spock beam down and find a small, one-person ship. A disheveled man named Lazarus appears, falls off a cliff, and gets hurt. Kirk has him beamed to the ship for medical care. Back on the Enterprise, Lieutenant Masters reports that the strange event drained the dilithium crystals in the warp drive. Starfleet sends a message saying every quadrant experienced the same vanishing effect and electronic problems. They worry this could be the start of an invasion and order all ships except the Enterprise to leave the area. Kirk is told to discover what is causing the disturbance.

Lazarus keeps flickering in and out of existence, meeting a lookalike enemy inside a “dimensional corridor,” which creates each energy wink. Spock finds a tear in space and time on the planet. Lazarus claims his enemy is trying to destroy the universe and causing the phenomenon. He demands dilithium crystals to fix his ship so he can keep fighting. Kirk says no. Lazarus steals dilithium from the Enterprise but gets caught. He denies stealing it and blames his nemesis. Kirk beams back down to the planet with Lazarus and a security team to find this enemy. Lazarus has another episode in the dimensional corridor and is sent back to sickbay. He then tells Kirk he is a time traveler, that his ship is really a gateway to the dimensional corridor, and that the planet below was once his home world. He says his enemy destroyed his civilization long ago, and he has chased that enemy for centuries.

Kirk is confused by how Lazarus switches—one moment he is hurt and crazy, the next he is strong and sensible. Kirk and Spock figure out that Lazarus is actually two different beings: one from this universe who is insane, and another from an anti-matter universe who is rational. They develop a theory that Lazarus’s enemy is his own counterpart from the anti-matter universe. If Lazarus and his anti-self ever touch each other outside the dimensional corridor, inside either physical universe, both the matter universe and the anti-matter universe would be destroyed.

Reception

Zack Handlen of The A.V. Club rated this episode a C− more than four decades after it first aired, calling its story baffling, unrewarding, and poorly paced. Hollywood.com ranked it 77th out of 79 original series episodes. In 2017, Den of Geek listed it as the sixth worst episode of the original series. CNET placed it ninth worst among all Star Trek episodes in 2016, based on audience and host rankings at a 50th anniversary convention in Las Vegas.