In Penzance, aboard a pirate ship, celebrations are underway. Young Frederic, an apprentice pirate, is finally recognised at 21 as a full-blown member of the band. As winter melts into spring and so to summer, we find the quaint old Cornish town bustling with life. All reject his advances except Mabel with whom he falls in love. In an attempt to protect them, the Cornish Constabulary is summoned to arrest the pirates.
Nothing goes as planned.