A power-hungry Leprechaun kidnaps Princess Zarina, a Dominian princess, on a distant planet, seeking to become king. However, a group of bumbling space marines, led by a mad scientist commander Dr. Mittenhand, thwart his plans. The Leprechaun is initially killed, but is reborn through one of the marines, wreaking havoc on the ship. Meanwhile, Dr. Mittenhand aims to use the princess to restore his own humanity. As the marines fight to survive, the Leprechaun transforms Dr. Mittenhand into a monstrous creature, planning to destroy the ship. The remaining marines must now stop the Leprechaun's evil plans and prevent the ship from being blown up.

Leprechaun 4: In Space
A mischievous leprechaun's cosmic adventure unfolds as he strives to capture the heart of a lovely princess, who is captivated by his treasure and determined to prevent its loss.