The day -- or rather the night -- of the big event finds expectant mother Katie quite calm, and Steve and Uncle Charley quite the opposite, and a hapless father to be off on Army manouvres. At the hospital, Katie gives birth to identical triplet boys and Steve must adjust to the fact that he is a Grandfather, three times over.

It may not be poker, but nine in the Douglas family is a full house. Feeling somewhat responsible, Robbie decides to quit school in order to pursue work full time and find a new home for his family. A wise school counsellor takes steps to discourage the move. Meanwhile Steve designs some plans for an extension to the house to accomodate the babies further.