With Christmas just around the corner, Agnes finds herself having to deal with her busiest Christmas yet. Trevor is visiting from the missions, while grandson Bono is sleeping over on Christmas Eve, and there are three new faces to feed on Christmas Day now that Agnes’s youngest son Dermot is the father of triplets. Before all of this happens Agnes needs to decorate the Christmas tree. Cathy plays a trick on Agnes after she opens her post.
With the festivities finally over, Agnes gets permission from the Bishop to stage her Nativity Play and rehearsals are in full swing. Agnes decides to cast herself in the lead role of the Virgin Mary, without knowing that Father Damien has offered the part of the narrator to her posh nemesis Hillary Nicholson.
The family get ready to celebrate the baptism of Dermot and Maria's triplets by hosting a party. Agnes and Winnie end up being put under the spell of the hypnotist booked to provide the entertainment.
Everything is about to change in the Brown household as two of Mrs Brown’s boys finalise their plans for new homes. Mark is busy preparing for his family’s emigration to Australia while Rory and Dino have found the perfect apartment in Kilbride. Cathy’s life could also be about to change, as boyfriend Professor Clowne reveals that he has a surprise proposal for her.
Agnes wants to treat herself to a holiday, but needs to find somebody to look after Grandad for a couple of weeks. Rory and Dino’s new apartment isn’t ready yet so Mrs Brown offers them a place to stay but isn't very pleased when Dino begins taking over the house.
Valentine’s Day is just around the corner, and it looks like love is in the air for everyone in the Brown family, even Grandad. Betty buys a sex education book to help her son Bono understand about the birds and the bees, but Agnes and Winnie also end up reading it.
Everything seems to be happening all at once for a stressed out Agnes. Rory and Dino have fallen out, and Mark and Betty have got their emigration visas and are getting ready to leave for Australia. Cathy quickly becomes suspicious after her mother takes a phone call from a solicitor and discovers that the solicitor’s firm specialises in adoptions and before long Agnes’ children are all left wondering who is really a Brown at all.
Rory and Dino prepare for their wedding and with celebrity wedding planner La La Doggy on board, it looks like it is going to be the wedding extravaganza of the year. Agnes is pleased to be back in her own house after having renovations done, but she’s not sure if her new kitchen was really worth the wait.
Christmas is fast approaching and no-one has a clue what Mrs Brown’s grandson Bono wants for a present. He's already posted his letter off to Santa and Agnes is determined to find out what he wants. She also decides to hold a family games night, but she finds it hard to control her temper after none of the guests will play by her rules.
Songs: Ralph Blane (performed by the cast) -- Have Yourself A Merry Little Christmas, Willie Phelps (performed by Brendan O'Carroll) -- The Merry Christmas Polka
Agnes is on a mission as she attempts to make sure that grandson Bono isn't sent to the infamous local primary school. She gets lumbered with a brand new houseguest, a homeless parrot, but is still looking forward to her New Year's Eve party until her guests begin cancelling.