Treasure hunter Pearl Pureheart seeks the treasure of the Illdo Armada, but pirates Captain Oil Can Harry and Swifty decide to take it for themselves.
The tale of the Trojan Horse becomes the backdrop as Oil Can Harry tries to capture the city of Queen Pearl Pureheart.
Harry poses as a vampire in order to put Pearl to rest, only to have Mighty Mouse put him to rest.
After saving Pearl and her TV studio truck from disaster, Mighty Mouse investigates a rock concert involving Mick Jaguar (Oil Can Harry in disguise), and his two talking speakers.
Pearl mines an underwater farm for future food sources, while Harry tries to capture her ship and use it to prey on other vessels. As always, it's Mighty Mouse to the rescue.
Oil Can Harry tries to cheat in various ski resort events, but is thwarted by his bumbling assistant and Mighty Mouse.
Moby Whale is caught by Oil Can Harry and Swifty. Pearl Pureheart gets in trouble while trying to free the whale, and only Mighty Mouse can free her and the whale.
Oil Can Harry becomes a "Werecat" and threatens Pearl Pureheart. Mighty Mouse saves Pearl and manages to break the curse affecting Oil Can Harry.
Mighty Mouse must save the galaxy from the evil cat Harry the Heartless and rescue Queen Pureheart in this animated children's adventure.