On a world where penicillin was never invented, Quinn is mistaken for his double, who is believed to be the cause of a massive epidemic. While he is imprisoned by a health agency, Wade shows signs of being infected and only Arturo can find the cure.

Rembrandt has arrived on his dream world, where his double is as popular as Elvis, but has been dead for eight years. As Rembrandt gets to enjoy the fame he's long since wanted, an old enemy plots to make sure he disappears for good.

A lightning bolt strikes the vortex during a slide, damaging the timer and trapping Quinn on the astral plane. Now the Sliders are stranded on a world with 1950s technology and Quinn can not be seen by the others. He tries to get the help from the only one who can see or hear him, a girl that has a history of hearing voices.

Wade witnesses a murder just before the slide, but as the Sliders land on the next world, the same murder is about to occur. This time, Wade intervenes and this gets the Sliders involved with a disgraced federal judge and a United States under martial law.

On a world where Prohibition was never repealed, Rembrandt's double is famous for fighting crime and corruption. Unfortunately, the trouble starts when the Sliders land in the middle of a wedding, where the groom and bride are from mob organizations.