Abstract:
Recipe for tension on the high seas:

An Australian billionaire and his movie-starlet wife,
A snobbish old lady chaperoning her nubile teenage great-niece,
A married couple of university music professors; she plays viola “badly”,
A bronzed California couple and their noisy, bratty kid,
A retired diplomat on his way to his old stomping grounds in Lisbon,
Two silent Portuguese men who keep themselves to themselves,

AND

Only one private bathroom.

No need to stir vigorously; this yeasty mixture of twelve passengers on a Portuguese freighter stirs itself up.