With Dessie, Fidelma and baby Rose back living with the Moones, the choirmaster sets to work on a new business to help him give his family their own home. But does Boyle really need a Catholic book shop? Liam isn't convinced, and starts building an extension in the garden instead, while Martin has his own building project - renovating his new `penthouse'.

Grandad's childhood imaginary friend George Gershwin, a cool, piano-playing guy, turns up to fulfil his bucket list., Martin takes an unusual approach to his exam revision.