Back in the summer, Martin and Padraic started building a raft. They planned to sail down the river into town, buy ice cream and frolic in the water. But now it's October and the raft still isn't quite finished. So instead, they'll make it a Halloween ghost ship.
Dressed as Ghostbusters (or are they the Super Mario Brothers?), Martin and Sean are joined by Padraic, in the guise of a beaver, and Crunchie Haystacks, doing his best The Undertaker impression, and together they embark on the voyage of a lifetime, complete with that well-known sea shanty, Orinoco Flow.
A spooky adventure ensues, however, when they land on wolf-inhabited Castle Island and meet Island Joe.
Meanwhile, at church, Father Roche is concerned when the pregnant, unmarried Fidelma takes to the altar to read at mass, charging Father Linehan to tell her she can't do so again. The progressive priest has a plan to have her reinstated, though.