Fitzhugh and Betty are captured by a paralysis ray, but whisked away from SID Officer Marad's cell by a teleportation device. The teleporter is Dr. Kirmus, who has built his own tricorder-sized teleportation device.
Marad has had Kirmus under scrutiny with the aid of her landlady, a secret SID spy. Kirmus says he can teleport things all the way to Earth, but the SID close in and capture him before he can show the Earhlings. Kirmus does free Fitz and Betty before he is caught. They and the others try to get to the teleporter, recovering a piece that Kirmus hid in his house.
Betty and Dan get captured, and Marad puts them in a freezing chamber to force Kirmus to work the teleporter. Mark and Valerie manage to free them, while Steve and Fitzhugh get to the teleporter. Fitzhugh just manages to locate Earth, but as the SID close in there isn't enough time to teleport there.
Activating a self-destruct sequence, Steve teleports out the others, than Kirmus, than himself, as Marad is caught in the explosion. Kirmus goes on the run, deciding not to build another teleporter for fear the authorities will get it and misuse it.