Hayley Mills plays twins who, unknown to their divorced parents, meet at a summer camp. Products of single parent households, they switch places (surprise!) so as to meet the parent they never knew, and then contrive to reunite them.

Mild mannered zoology professor Dr. David Huxley is excited by the news that an intercostal clavicle bone has been found to complete his brontosaurus skeleton, a project four years in the construction. He is equally excited about his imminent marriage to his assistant, the officious Alice Swallow, who is interested in him more for his work than for him as a person. David needs the $1 million endowment of wealthy dowager Mrs. Carleton Random to complete the project. Her lawyer, Alexander Peabody, will make the decision on her behalf, so David needs to get in his favor. However, whenever David tries to make a good impression on Peabody, the same young woman always seems to do something to make him look bad. She is the flighty heiress Susan Vance. The more David wants Susan to go away, the more Susan seems not to want or be able to. But David eventually learns that Alexander Peabody is her good friend...

Fran Garrison's all in a tizzy because her prize Dachshund, Danke, is having pups, and she has hopes of one of the pups becoming a champion. But at the vet's, her husband Jim is talked into letting Danke wetnurse a Great Dane pup that's been abandoned by his mother. And Jim wants to keep the Great Dane. But Brutus has this problem: he thinks he's a dachshund and he's too big to be a lapdog. But when Fran ridicules Brutus one too many times, Jim's got a plan to prove to everyone (and Fran) that a great dane can be far more than just an ugly dachshund.

A Parisian tailor finds himself posing as a baron in order to collect a sizeable bill from an aristocrat, only to fall in love with an aloof young princess.