Giants Mollusks are released from the earth by an earthquake and start killing people.

It’s the off-season at the lonely Beauregard Hotel in Bournemoth, and only the long-term tenants are still in residence. Life at the Beauregard is stirred up, however, when the beautiful Ann Shankland arrives to see her alcoholic ex-husband, John Malcolm, who is secretly engaged to Pat Cooper, the woman who runs the hotel. Meanwhile, snobbish Mrs Railton-Bell discovers that the kindly if rather doddering Major Pollock is not what he appears to be. The news is particularly shocking for her frail daughter, Sibyl, who is secretly in love with the Major.

Unhappily married, Julia Sturges decides to go to America with her two children on the unsinkable Titanic. Her husband, Richard also arranges passage on the luxury liner so as to have custody of their two children. All this fades to insignificance once the ship hits an iceberg.