While working in the lab, scientist Peter Brady gets exposed to a radiation leak and becomes invisible; the British government wants to classify him as top secret and lock him up, but he escapes.

Military Intelligence asks Peter to undertake a mission to rescue an intelligence operative. To free the man, Peter and a local resistance fighter must breach the high-security hospital and get the operative out.

A disfigured tycoon tells Peter he wants to become invisible, but his motives have political implications.

A defecting Russian scientist (Zena Marshall) is kidnapped before she can help Brady regain his physical form. Hanning: Lloyd Lamble. Dushkin: Rupert Davies. Sally: Deborah Watling. Diane: Lisa Daniely. Phillips: Noel Coleman. Porter: Alexander Dore.

Peter's existence as an invisible man becomes public knowledge, while Sally's friend needs help when her stepfather plots to kill her mother.

An actress becomes the target of a blackmailer after accidentally causing the death of a homeless man.