A tough young girl lives with her aging grandfather near a cove on the coast of Cornwall. She supports herself and him by gathering seaweed to sell as fertilizer. A cocky young neighboring boy decides to help her with the work.
| Actor | Role |
|---|---|
 Donald PleasenceMalachi | Malachi |
 David BradleyBarty | Barty |
 Veronica QuilliganMally | Mally |
 Peter VaughanMr. Gunliffe | Mr. Gunliffe |
| LLillias WalkerMrs. Gunliffe | Mrs. Gunliffe |
 Arthur EnglishJack Combes | Jack Combes |
| DDavid HoweJake Combes | Jake Combes |
| KKennaley HoyleMatt Combes | Matt Combes |
 John BarrettPolwarth | Polwarth |
| AAlan HockeyDr. Petherick | Dr. Petherick |
 George MalpasMr. Eliot | Mr. Eliot |
 Meg Wynn OwenMally's mother | Mally's mother |
| PPeter WyattMr. Carew | Mr. Carew |
| DDavid FoxxeSolicitor's Clerk | Solicitor's Clerk |
| DDerek CarpenterDoctor's Assistant | Doctor's Assistant |
| CClaire DavenportLady in Store | Lady in Store |
 Linda RobsonGirl in Store | Girl in Store |
 Pauline QuirkeGirl in Store | Girl in Store |