Several months after getting married, Mollie and James welcome their child, Mikey’s half-sister Julie into the family. While at first, Mikey is excited to be a big brother, he begins to resent his sister shortly after she is born when the reality does not match what he dreamed being a big brother would be like.
He finds Julie annoying and resents sharing both toys and his parents attention; being constantly mean to her as a result. In turn, Julie is not impressed by Mikey, who struggles with potty training, having several accidents despite encouragement from his friends and family. James is provided a job as a full-time pilot thanks to Mollie’s parents and the longer work hours strain the couple’s relationship.
The couple also has parenting disputes with James believing Mollie to be overprotective and too high-strung. Mollie’s lazy younger brother Stuart comes to live with them temporarily, and James is upset that Mollie does not even consult him about it. James is further frustrated when Stuart pulls an (unloaded) gun on him thinking he’s an intruder. He wants Stuart out immediately, and Mollie insists on talking to him first seeing nothing wrong with him having a gun or leaving messes everywhere.
During one of James’ visits, he takes Mikey and Julie to the movies. Mikey finally realizes he was too hard on his sister and she wasn’t to blame for their dad leaving. Later, when Julie decides she doesn’t need Mikey and wants to strike out on her own, she is inspired to walk unsupported.
Mollie sees this and showers Julie with affection for her accomplishment, the happiness is short-lived however, as James is not there to share the moment. James returns home to talk to Mollie, and Mikey accomplishes going to the bathroom on his own, which is a celebration both of them share with him.
James is due to go flying despite a massive storm building in the area, Mollie gets worried and leaves Mikey and Julie in Stuart’s care. While she is gone, a robber sneaks into the apartment, and Stuart scares him out with his gun, forgetting that Mikey and Julie are in the apartment. Stuart gives chase leaving them home alone with a fire starting in the apartment.
Thinking quickly, Mikey pushes Julie in her bouncer out of harm’s way. Meanwhile, James and Mollie make up in the plane when the flight is canceled. James asks Mollie if she’s happy about being right; she tells him that she loves him and no longer cares about who’s right.
They return home to see the fire through the kitchen window. Momentarily panicked, they are relieved as Mikey exits the elevator with Julie in tow. James puts out the fire before any major damage is caused. Mollie admits that leaving the kids with Stuart was a bad idea which James is pleased to hear.
At a family barbecue, Julie and Mikey have a conversation on how strange adults are. Julie is grateful to Mikey for saving them from the fire and he sees how much they are needed in each other’s lives. He tells Julie that it’s them against the grown-ups and that he loves her.
She agrees saying “big ones don’t make any sense” and the two walk off together hand in hand.
Don’t miss the chance to watch Look Who’s Talking Too and witness this heartwarming family story unfold. Gather your loved ones and enjoy the movie together!