Alison is quite taken with Hank Martin, a long haired philosophy professor. That has Grandfather Pruitt worried so he invites himself along when the young couple have a excursion in the countryside.
The Endicotts are invited to a glamorous film premiere but Pokey is determined to young to attend. Grandpa is volunteered as a babysitter and the two family members are resentful. Pokey is ready to be treated as older.
The Endicotts encounter a forlorn waif named Paulo who happens to be mute and a bicycle thief. After getting to know him Penny begins to lobby her father to adopt the young Italian.
Uncle Charley plus Robbie and Katie Douglas visit the Endicotts. Charley wants Mike's help in finding a girlfriend from WW II. The young Douglas couple hope to enjoy a second honeymoon.
Michael is temporarily lacking cash when his old college roommate Bill makes him a tempting offer. Bill owns a trendy Rome nightclub and he wants to make Endicott the manager.
Love is in the air for two members of the Endicott clan. Grandpa Pruitt is smitten with Mrs. Kinneman, an attractive widow from Illinois. Alison falls for Jerry, a boy next door type from Iowa.
Penney and Pokey secretly leave home as they feel they are impeding Michael's marriage to a fashionable stewardess. A frantic search for the missing girls ensues.
Signora Vitale's very pregnant niece Christina is visiting and unexpectedly goes into labor. The Endicott household is thrown into an uproar, a doctor is unavailable and Grandpa Pruitt's dubious delivery skills are called upon.
While making her film debut in an underground film Alison decides the hippie lifestyle looks appealing. She informs her dad Mike she wants to wander Europe as a vagabond.
Endicott finds that he has something in common with visiting professor Mrs. Okada, rebellious daughters. Her child is intent on ditching Japanese traditions and adopting western customs.
The Endicott family meet Sally, a young girl leading a vagabond life. They take her in and try to smooth over her rough edges so Sally feels more comfortable around others.
The Endicotts are being evicted from their apartment because the building is to be torn down. But Grandpa has a plan and use his wheeling and dealing skills to save their home.