Garry Goodrow

Expecting the usual tedium that accompanies a summer in the Catskills with her family, 17-year-old Frances 'Baby' Houseman is surprised to find herself stepping into the shoes of a professional hoofer—and unexpectedly falling in love.

Matthew Bennell notices that several of his friends are complaining that their close relatives are in some way different. When questioned later they themselves seem changed, as they deny everything or make lame excuses. As the invaders increase in number they become more open and Bennell, who has by now witnessed an attempted 'replacement', realises that he and his friends must escape or suffer the same fate.

San Francisco Bay, January 18, 1960. Frank Lee Morris is transferred to Alcatraz, a maximum security prison located on a rocky island. Although no one has ever managed to escape from there, Frank and other inmates begin to carefully prepare an escape plan.