The Goodies (1970)

S3E5 For Those in Peril on the Sea

Graeme becomes obsessed with retracing a legendary Viking voyage to uncover the fabled Lost Island of Munga. His relentless enthusiasm drags the Goodies into a chaotic seafaring adventure, but their journey quickly unravels when their vessel is wrecked. Stranded and vulnerable, they find themselves facing a familiar adversary from an earlier escapade, whose grudge threatens to turn their quest into a fight for survival.