Agnes Brown has family troubles to contend with: her son Dermot has fallen out with Maria Nicholson, his long-term girlfriend, and Grandad is feeling poorly. After a sleepless night, Mrs. Brown decides to try to sort out Dermot and Maria's problem by giving Maria the benefit of her advice. But her heart-to-heart with Maria only succeeds in making the dispute worse.

Agnes Brown worries that her family is keeping too many secrets when Cathy will not reveal any information about her new boyfriend, Mark will not confess why his wife has thrown him out and Dermot lies to his fiancee's parents about the status of his job

Agnes becomes concerned when Dermot announces he wants to ask his childhood friend Buster, a known criminal, to be his best man. Mrs Brown is distracted when her neighbour Winnie's husband is rushed to hospital, leaving her son trying to raise money for his wedding by becoming embroiled in a money-making scam with his friend.

Dermot's pre-marriage nerves get the better of him and he locks himself away in a cupboard, so it is up to Agnes, Fr Quinn and best man Buster to try to calm him down. Meanwhile, Rory tells his mother he is gay.

Newlyweds Dermot and Maria argue over whether they should buy their own home. Meanwhile, Mrs Brown tries to make Grandad happy by secretly staging a funeral for him, but the plans go awry when she mistakes two Mormons - who have been stealing Father Quinn's parishioners - for the men who are supposed to be delivering the coffin.