When Reno entertainers Soren and Frederica lose their prized animal, a trained dolphin, they call upon Arthur (they know his parents), and he and the Tick come to their aid. Little do they know that the dolphin, The Fin, plans to rule the world with his newly-invented Fish Magnet, with which he plans to bury the city in fish. The Tick must cope with his newfound weakness - gambling addiction - but manages to overcome it and beat The Fin by holding his breath longer.
