The stooges are tricked into becoming stowaways by their neighbor "Borscht", a spy for an enemy country. Stranded on a freighter on the high seas, they discover that their friend has concealed some stolen microfilm in watermelons they brought aboard for him. After a wild chase, they subdue Borscht and recover the microfilm.

"The Stooges foil a spy carrying secret microfilm in watermelons."