The Egg, floating on a giant prehistoric egg in the middle of the ocean, is Britain's most remote prison. So there's no better place to send Patsy Potts, one of the nation's most tricky prisoners, who's a master of disguise and escaped from every other prison they've tried to keep her in. But when Tim arrives on The Egg with Patsy in the helicopter, she's nowhere to be found, and worse, no-one knows what she actually looks like...