Rising up from the Irish Sea lies the ancient kingdom of Mourne, a rural area in the east of Northern Ireland that teems with animal life. It's March and the start of the birthing season. The founder of the oldest veterinary practice in Downpatrick, Maurice King, receives a call about an extraordinarily rare birth on a farm he knows well. He heads straight out to check on the new arrivals. Also out on the road is vet Rachael Frew, Maurice's most experienced vet in the Downpatrick practice. Rachael gets an emergency call to a smallholding where a goat has been attacked by a donkey. Is it too late to save the goat's life? At the foot of the Mournes, in Newcastle, Maurice's son Cahir runs a smaller, sister practice. Cahir has an appointment with Boo, a pedigree bulldog whose owner would like her to breed. Boo has been unable to do so naturally, so bulldog Bailey has also been booked in to provide the semen that Cahir must collect to inseminate Boo.

It is a busy start to spring and the birthing season in the Mournes is reaching its peak. It has been raining for days and vet Maurice King is called into the practice car park to examine a newborn lamb that is in danger of succumbing to hypothermia. Farmer Stanley brings in a heavily pregnant ewe. Her waters broke hours ago but there is no sign of any lambs. Vet Rachael Frew examines the ewe and realizes that her cervix has not opened. The lambs are stuck and there is a risk the placenta could be ruptured and cut off their oxygen supply. Rachael decides to perform an emergency cesarean but will she be able to save the lambs? In the clinic, dachshund Flame arrives with owner Oliver. Flame is suffering from intermittent pain. Newly qualified vet Daisy Dillon gives Flame a thorough examination but can’t find anything wrong and asks owner Oliver to come back if the symptoms continue. A few days later Oliver and wife Teresa return and the decision is made for Flame to undergo a general anaesthetic so that she can be x-rayed – but can Daisy get to the root of the problem? In the foothills of the Mournes in the town of Castlewellan, the largest vet practice in the area, Castle Vets, is in the middle of another hectic day. Vet Aidan O’Hare heads to a cattle farm to pregnancy test some cows. He knows the farmers well and he is invited in for tea once the work is done. It is Rachael’s turn on the night shift and she is called out to a farm where a cow is having trouble giving birth. It’s habeen a long winter with many pregnant cows kept inside feeding on rich silage. The result for some cows is bigger calves and Rachael must use a jack to assist her in getting this calf out - but it is a struggle. Further east in the coastal town of Portaferry, two grey seals wait for vet Cahir King to assess whether they are fit for release back into the wild. Aquarist Amy Robinson explains how Comsec and Leo were found at just a few weeks old. They are now six m

Warmer weather finally arrives in the Mournes. The racing season is getting underway and the vets face a rush of emergency operations. Vet Maurice King and his son Cahir are called out to a colt recently bought at the horse sales. Ollie’s owner Fergal has high hopes for him as a racehorse, but before his training starts he would like to have him castrated. It is a common practice but a delicate task that requires just the right level of sedation to ensure it is painless while keeping the patient standing. Downe Vets’ youngest vet, 24-year-old Miriam Campbell, heads to a pre-booked appointment with fourth-generation cattle and sheep farmer Paul Brennan. Paul needs Miriam to tell him whether two of his cows are pregnant. His farm is in a beautiful spot on the side of the mountains overlooking the Irish Sea. In the town of Castlewellan, young sheepdog Ellie is waiting with owner Stephen to be seen at Castle Vets. Ellie badly tore her leg open on some wire the week before. A vet at a different practice stitched up the wound, but it became infected and her stitches have burst open. Specialist small animal surgeon Martin Fitzpatrick assesses Ellie and books her in for an urgent operation to try to save her leg. In Downpatrick, the reception is bustling with pets and their owners. Whisky the chow-chow comes in with owner Gabriel to get his ears checked by vet Cahir, and Gabriel has another unusual pet in the boot of his car for Cahir to see. On the road, senior vet Rachael Frew is on her way to a dairy farm to see a cow with a suspected displaced stomach. It is a life-threatening condition that can happen during calving. Rachael confirms the farmer’s suspicions by listening to the sounds inside the cow’s stomach. She decides to operate immediately and move the stomach back into place by hand – but it is a tricky operation and she has no choice but to ask the farmer to assist.

At the mixed practice in Downpatrick, the vets treat farm animals and pets and in the spring concerned locals often bring wild animals into the clinic. A pregnant dog is rushed in to surgery. Cocker spaniel Tilly has been in labour for 12 hours and is struggling to give birth. It is a potentially life-threatening situation and vet Maurice King decides to perform an urgent caesarean section. It is a huge and valuable litter but can Maurice save Tilly and her pups? A young jackdaw has been brought into the clinic. He was found under a tree and is unable to fly. The vets rehome him with Belinda, a local woman who has Asperger’s. Belinda has a particular affinity with animals and at home she hand feeds him and encourages him to use his wings on short test flights At Tullyraine Equine Clinic, vet Hugh Suffern examines mare Echo, who has a lame hind leg. Owner Alex trusts only Hugh with Echo’s treatment but it is unclear exactly what is causing her lameness. Alex has spent years training Echo in eventing and if Hugh can’t fix Echo’s leg, her sporting career will be over. At the Downpatrick clinic Dexter - a therapy dog at the local hospital - is brought in to see vet Rachael Frew. Dexter has had cancerous lumps on his skin before and owner Lavinia is concerned about some new lumps that have recently appeared. Rachael books him in for an operation to remove the lumps but they must wait for the results of tests to find out whether the cancer has returned. In the town of Newcastle, Maurice’s son Cahir King runs Downe Vets’s sister practice. Umbrella cockatoo Brolly has an appointment to get her nails clipped but it is not something she enjoys. Maurice is booked in to assess the hooves of some semi-feral ponies and tries out a new blowpipe that he will use to sedate them. Maurice also has an appointment to provide a horse with a passport, and vet Daisy Dillon heads out to inoculate some puppies that will form part of a pack of hounds for a local hunt in N

A calf born with an extraordinarily rare condition is brought in to see vet Martin Fitzpatrick at Castle Vets. Castle Vets also run an obesity clinic, and head nurse Julie Hurst has an appointment with seven-year-old cat Paws, whose weight has been steadily increasing over the last few years. Paws suffered a traumatic road accident in which she lost a leg, and getting her weight down is crucial. Owners Amanda and Martin are given strict instructions but will they follow Julie’s advice? Vet Aidan O'Hare heads out to see Limousin bull Navarn, who has mysteriously gone lame. It is a blow to his owners, the McPolins, who earn their living raising and selling pedigree breeding bulls. If Navarn can't be successfully treated, he will have be sold for meat at a serious loss to his owners. At the stud at Tullyraine Equine Clinic, breeder John has booked in his mare Sweetbriar Rose to mate with stallion Conduit in the hope of producing a prize racehorse. Sweetbriar Rose is 'teased' by a male pony to get her ready to mate with Conduit and the mating goes well, but will it result in a pregnancy? At the clinic in Downpatrick, two superstar northern inuit hounds from Game of Thrones are brought in to see Maurice. One of them has painful sores on his paws. Two-year-old labrador Cooper is next to be seen. His owners, the Flanagans, are very worried about him after finding blood in his urine. Vet Daisy Dillon keeps him in for tests, and it soon becomes clear that Cooper's blood count is dangerously low. Over the next few days, the entire team at Downe Vets are involved in Cooper's treatment in a bid to save his life.

After the busy birthing season, life is less hectic for the mountain vets. For vet Maurice King, it is a less pressured time of year and a chance to enjoy the rewards of the job. At his practice in Downpatrick, Yorkshire terrier Mackie comes into the clinic with owner Liliane. Liliane is worried about Mackie’s lack of appetite. Her other dog Sonny died two weeks ago and she thinks Mackie is suffering from a broken heart. Vet Miriam Campbell books him in for a series of tests. Vet Rachael Frew heads out to a pre-booked appointment with a farmer she knows well. Damien produces meat from a large herd of Dexter cattle. His prized possession is bull Charlie, who has won several awards. Damian has had his eye on a young bull to follow in Charlie’s footsteps, but it is not working out. At Tullyraine Equine Clinic, today’s patient is ten-week-old colt Beau. His owner is concerned that one of his legs isn’t growing as straight as it should. Vet Inge D’Haese uses her skills to carry out a tricky procedure to correct his stance. At home, Tullyraine stablehand Caroline prepares her cow Daisy for her first ever competition at Northern Ireland’s biggest country fair, the Balmoral Show, where farmer Damian is also showing his bull Charlie. It is a new day and Miriam is rushing to an emergency at a local farm. She has been called to a local farmer who has a ‘cow down’. Miriam explains that if a cow is unable to stand up, it could be a sign of mineral deficiency, in which case the cow could die within hours – but the treatment for mineral deficiency can also be fatal. Maurice heads over to marine life sanctuary Exploris to give a new litter of otter pups their first health check. They belong to the centre’s resident family of Asian short-clawed otters, an endangered species. Rookie vet Daisy Dillon is called out to an emergency at a local farm. A cow has a ruptured a vein and is losing a lot of blood. It is the first emergency of this type that Daisy has had to