What's on TV this week: Fortitude, Code Black, Call the Midwife and more

Call the Midwife
Sunday, BBC One, 8pm
The staff of Nonnatus House don't have to deal with shark bites, but in the new series of they will have to contend with Sister Ursula, who has some unpleasant surprises in store. After travelling to Africa to help out at an ailing mission, the midwives return to Nonnatus House to find Sister Ursula in charge of the hospital, and hell-bent on making sweeping changes.

Apple Tree Yard
Sunday, BBC One, 9pm
Beware charismatic strangers lurking in the crypt beneath the House of Commons – especially if you're a renowned genetic scientist with a husband, two grown-up kids and high-flying career to lose. Emily Watson stars as Dr Yvonne Carmichael, whose dalliance with the mysterious Mark Costley turns into a full-blown affair, and threatens to destroy her perfect life. This four-part drama is adapted by Amanda Coe from Louise Doughty's best-selling novel.

Horizon: Hair Care Secrets
Monday, BBC2, 9pm
With access to the research laboratories of some of the world's leading hair care companies, including L'Oreal and ghd, Horizon explores the latest research and technology around hair care. These investigations also reach some interesting conclusions about whether those expensive shampoos really are better than the bargain-basement variety.

The Cult Next Door
Thursday, BBC2, 9pm
Documentary by acclaimed director Vanessa Engle tells the story of a strange cult which came to light in 2013 when news broke about three women emerging from a small flat in South London after decades in captivity. Tracing the group back to its roots in the 1970s, the film describes how its leader, Aravindan Balakrishnan, believed in an international communist revolution and created a tiny political sect that followed the teachings of Chairman Mao. The film documents how this collective evolved into a bizarre pseudo-religious cult, where members were controlled, threatened and brainwashed into never leaving the flat.

Code Black
Thursday, RTÉ One, 10.15pm
Rob Lowe joins the cast as the explosive medical drama returns for a second series. Lowe plays Colonel Ethan Willis, a Department of Defence medic, with Marcia Gay Harden returning as the hard-nosed Dr Leanne Rorish. The series starts off with some serious action, as Dr Willis races by helicopter to the scene of a shark attack in Malibu. Code Black is what happens when a hospital's resources are overwhelmed by the sheer number of patients – don't say that to Simon Harris.

Fortitude
Thursday, Sky Atlantic, 9pm
The British drama is back for a second, chilling series, with new cast members (well, someone's got to replace all the characters who met a grisly end in the first series) and fresh horrors facing the town's few remaining inhabitants. Sofie Gråbøl returns as the town's governor, Hildur Odegard, and Dennis Quaid joins the cast as crab fisherman Mike Lennox, one of the few people who haven't fled the town. Also joining the cast are Michelle Fairley, Parminder Nagra, Ken Stott and Irish actor Robert Sheehan. As series two opens, the town of Fortitude is settling back into what passes for normal life, but former sheriff Dan Anderssen (Richard Dormer) is still nowhere to be found, and the terrible events of the last series cast a pall over the community.

Urban Myths
Thursday, Sky Arts, 10pm
The series has already attracted controversy due to a (since-pulled) episode based on a story about Michael Jackson, Elizabeth Taylor and Marlon Brando going on a road trip in the aftermath of the 9/11 attacks. Jackson's family were not amused when footage emerged of Joseph Fiennes playing the late King of Pop. This week's episode (re)imagines the friendship between Samuel Beckett (played by David Threlfall aka Frank Gallagher from Shameless) and Andre the Giant. The playwright, living in France, drove the young Andre to school every day, as the 12-year- old had already grown too big for the bus.

The Graham Norton Show
BBC One, 10.35pm
Sit back and crack open a lager, lager, lager as Norton presents a special Trainspotting-themed evening of chat featuring Danny Boyle, director of the eagerly awaited sequel, Ewan McGregor, Johnny Lee Miller and Robert Carlyle.