Granny Baby / Time Is Money

S1, E4: Jimmy's Granny comes to stay while Judy and Hugh are off on a third honeymoon.  Jimmy, concerned by her ailing health, gives her his new youth tonic.  However, the potion works too well - Granny ends up as a talking baby! Through the wonder of time travel, Jimmy goes 15 years into the past to a time when his parents were swinging sweethearts.  Jimmy's investment tip changes the future so that the Neutrons become fabulously rich - but with unintended consequences!