Biff books the group on a tanker to Amsteraqua after another gig falls through, this being the cheapest way to go straight there. The Piranha has designs on ruling the Underwater States of America and captures the tanker for its load of special rocket fuel. The Neptune's scuttle the Piranha's rocket practically dismantling the control center and messing with the rocket's fuel delivery system. Jabber manages to launch the rocket accidentally to a different destination, with its cargo of sleep dust.
