The Gallaghers' return for a fourth series, and its Lip's 18th birthday but not all is going to be clean sailing as there’s a few surprises ready to hit him. First the Maguires expect him to do something for them. But the biggest shock of all is his long-lost mother Monica turning up out of the blue with a bombshell that could turn their lives upside down.

Frank’s desperate to keep the fact that he’s still married to estranged wife Monica from Sheila, and Monica’s not making it easy for him. But Sheila can see that she has competition for Frank and sets about trying to reunite Monica with her estranged lesbian lover. But is Monica still a lesbian?

Monica manages to seduce Frank and sink her claws back in, but he dare not tell Sheila that he and Monica have been sleeping together. Sheila proves to be a frightening adversary when scorned and Frank could be in real danger. But neither Sheila nor Monica want to share him and he has to decide on which wife he wants. But who will he choose?

Ian gets more than he bargained for when a new person enters his life. Another death in the Maguire household causes Mimi to think the family may be cursed.

Debbie's glad to have her dad back at home, but Monica's not happy with all the attention Frank is giving her and tells her it's time she found herself a boyfriend. Also Ian catches the eye of someone he least expected.

Explosions across the estate spark fears that Chatsworth is a terrorist target. But it has the Maguire's worried that they're under threat from folk a little closer to home when Patrick finds the family semtex missing. Meanwhile when Frank reveals to Monica she was never his first choice over Sheila, Monica vents her anger by turning to Norma for gifts and goodies.

Learning of the death of his three ex-cell mates is sending Paddy round the bend. With the three of them taken out one-by-one in suspicious circumstances, could this mean he's next in line?