Alan, Terry, and Graham are three best friends who still act like children when they get together. During Terry's stag do, they decide to prank their fearsome old teacher but they end up scaring the old man to death.
Graham finds out that his wife Molly got pregnant while at school and gave the baby up for adoption. Meanwhile, Alan employs both Terry and Graham much to the chagrin of their wives who hate him.
After Pat's death Alan begins feeling guilty and is haunted by nightmares and noises he thinks are ghosts. Meanwhile, Pat's ex-husband wants to take the children away from Terry and Graham tracks down Molly's son.
With three deaths on their conscience, the boys' friendship deteriorates as Terry and Graham realize what a toxic person Alan is. The father of Molly's son is revealed and everything comes to a head at Alan's Roman-themed dinner party.