In a quiet suburb, young Peter faces a real nightmare: his beloved grandfather, whom he has always admired, is moving into his house. What should be a way to strengthen the bond between grandparents and grandchildren turns into a battle of wits and pranks when Grandpa Ed decides to take over Peter's room, forcing him to move to the attic. As their living situation becomes increasingly tense, Peter doesn't sit idly by and launches a surprise attack with a series of pranks that would make any rival tremble.
From elaborate traps to gags involving chickens and water balloons, the war will escalate to comedic and absurd levels. However, what starts as a playful rivalry soon reveals the deep love and connection that unites the two generations. In the process, Peter discovers that his grandfather is not just a rival, but a man full of stories, wisdom, and a surprising past that will help him grow up and understand the importance of family.
With a cast featuring big names like Robert De Niro and Oakes Fegley, this family comedy blends laughter and life lessons into a fun and heartfelt narrative. In the end, Peter and his grandfather will realize that, although the war was intense, family love always prevails and strengthens in the most unexpected moments.