Legally the French may not fish within a three-mile limit of the British coast, and vice versa, and breaches of this rule are the cause of frequent spats between the two countries.

In this instance, hot-headed Cornish harbour-master Nat Pomeroy confronts Lanec Florrie, an equally redoubtable widow in charge of an otherwise male crew, from a Breton port.

Widower Nat's daughter, Sue Pomeroy, has been friends since childhood with local boy Bob Tremayne, and their eventual marriage has been taken as a foregone conclusion.

Bob is called up to serve in the British navy, and in a showdown conversation with Yan before he leaves, the two agree that Sue must be allowed to follow her own heart.

With most men absent, a loose sea mine drifts into the Cornish harbour and Lanec bravely mans a ship to net it and tow it out, making her a local hero and easing the tensions.