Joe Holt, a minor employee of the Armstrong Rubber Goods and Swimming Wear Company, has invented an unsinkable bathing suit. His ambitions make him the butt of practical jokes perpetrated by the other employees, who convince him that Mr. Armstrong, the head of the company, is interested in his invention. On the contrary, Mr. Armstrong will have nothing to do with Joe, so when a lawyer informs him that he has inherited his aunt's fortune, Joe is suspicious. Finally convinced, Joe quits his job, only to find when he arrives in California that his aunt's entire fortune consists of worthless stock. In its place, she has left him to care for Sam Wellington, the son of a servant. Completely broke, Joe and Sam apply for jobs on Catalina Island. Just before the boat leaves, socialite Alice Brandon takes him in hand, announcing that they will stay at the house of Tom Brandon, her father. Alice has mistaken water-fearing Joe for Joe Holt, the marathon swimmer, who is to swim in a race across the Catalina Channel. Joe tries to tell Alice the truth, but she is too busy confessing that she has fallen out of love with Ed Dover, another competitor, to listen and begs Joe to beat Ed for her sake. Joe Holt, the swimmer, meanwhile, has been jailed as an imposter. Sam tries to teach Joe how to swim, but the effort fails until Joe acquires an unsinkable suit. After his attempts to avoid the race fail, Joe dons the suit and swims across the Channel, winning the race by hitching a ride on a shark. His win secures Alice's love.