Ken Wilberforce is building a robot he has named Metal Mickey. It becomes sentient when girl next door Janey feeds it a Galactic Fizzbomb. Now all Ken and his siblings have to do is to convince their dad that Mickey can be useful around the house so he will let them keep him.
Granny and Metal Mickey have done Steve and Haley's homework. Mickey's answers are so outstanding that the teachers immediately suspect foul play and end up deducing Gran is scientific a genius.
Mickey acquires the power to reproduce money in order to replace father's plants and Granny ends up on trial for counterfeiting.
Burglars Jonathan and Harry break into the Wilberforce home and decide to kidnap Metal Mickey and hold him for ransom. However, Mr. W has no intention of paying. Not even when Granny stumbles upon the burglar's hiding place and gets kidnapped as well.
Father warns his family that he is expecting his boss Mr Barraclough and his wife to call that evening, and that everything in the house must be tidy for the visit. Then, Mickey gets hiccups...
News of walking-talking robot Metal Mickey starts to spread. Naturally, the government boffins want to take him to pieces. But Mickey's young friends won't let that happen.
Haley is sweet sixteen and Mickey's transistors glow with love. But rejection is a bitter pill when she tells him she prefers human company.
Mickey makes music - and is an overnight sensation! How can the family cope with his sudden success?