First of two reunion movies starring the original cast of the popular 1950's series "Father Knows Best." Jim and Margaret Anderson invite their children and grandchildren for a visit to celebrate their wedding anniversary.
Jim Anderson is worried about his wife Margaret, who is suffering from empty-nest syndrome now that the children are grown. Since they have a wedding anniversary coming up, he secretly arranges for all the children and grandchildren to come home for a visit. Betty is widowed and lives in Chicago with her two young daughters, Ellen and Jenny. She is a buyer for a major department store. Bud, his wife Jeanne and their son Robbie live in Minneapolis. He arranges and participates in motorcycle races and also owns a shop. Kathy is a single teacher living in Kansas City. They all arrive on the same flight and are met at the airport by Jim and Margaret.
Betty's former boyfriend Frank, whom she hasn't seen in many years, is the plane's pilot. She invites him to join the family for dinner but later confides in Margaret. Betty feels that pursuing a relationship with Frank would be a betrayal of what she shared with her late husband. Margaret tells her not to live in the past.
Jeanne is not with Bud and Robbie. He explains that she stayed behind to take care of pressing business but may follow in a day or two. Jim senses that all is not well between them, which Bud confirms. She dislikes his being gone so much and feels he needs to spend more time with Robbie. Unknown to Bud, Jim telephones Jeanne and asks her to come. She arrives the following day.
Kathy's doctor boyfriend, Jason Harper M.D., arrives unexpectedly and is given a warm welcome. While she is pleased to see him, she is somewhat annoyed when he asks her again to marry him. He thinks it is because he is ten years her senior but that is not the case. Kathy is simply not ready to get married.
To Jim and Margaret's consternation, everyone deserts them on the first night. Betty has a date with Frank. Bud's old friend Leo invites him and Robbie over to meet his family. Kathy's high school friend Mary Beth takes her and Betty's daughters to the boat show. Jim and Margaret decide to go out but they have no transportation. Earlier Bud was giving his father's car a tune-up and left the carburetor in the sink.
Kathy teases Betty about Frank, which annoys Betty and sharp words are exchanged. Margaret intervenes and tells them not to quarrel. Betty states that she doesn't want to discuss Frank, which Kathy reluctantly accepts. The entire family, along with Frank and Jason, attend church. Jim has a flashback about the time Betty insisted they renew their wedding vows, complete with a clip from the original show.
Bud and Jeanne discuss their problems. He agrees that he needs to be home more. Robbie finds his father's old pup tent in the attic and wants to camp out in the back yard. After Bud is asleep, Robbie sees what he believes to be an intruder trying to break into the house. He wakes Bud, who recognizes Kathy and tells Robbie he's going to scare her. But when he leaps out at her, she takes him down with self-defense. The entire household is awakened and Bud is rescued.
The family takes a picnic to Clear Lake and the children wander off to fish. One of Betty's daughters gets into a canoe and the rope tying it to the dock breaks. Her sister and cousin have already returned to the picnic area and no one hears her screams for help as the canoe drifts away. When her absence is finally discovered, there is no sign of the canoe. The adults separate and circle the shore, while a frantic Betty sobs in fear. The empty canoe is found beached near a small waterfall. Just as Jim is leaving to get help his granddaughter appears, soaking wet but safe.
With too many helpers in the kitchen getting in her way, Margaret escapes to the front porch for a breath of fresh air. Jim joins her and they kiss, prompting a passing teenage couple to jeer at them. Later at the anniversary dinner, Jim honors Margaret with a beautiful toast about how much she means to him.
The next morning everyone leaves, promising to return soon. Jim reminds Frank to be careful flying his cargo of Andersons. Kathy hints to her mother that perhaps she will marry Jason before their next visit. The cars drive away, leaving Jim and Margaret on the porch. They embrace and are again jeered at by the same teenage couple.