Chevin Chase veterinary practice is buzzing with excitement. The finishing touches are being made to the marquee in the garden with flowers arriving and tables being laid. Eight months pregnant Anna is directing the activity but begins to panic. Time is ticking away and her father George, the groom, is still operating on a puppy. Meanwhile in London, Sarah walks out on her cheating boyfriend David and drives up north. The church is packed to the rafters. Practice Manager Deborah is making disparaging remarks about everyone to her husband Rick, the practice Senior Partner. During a brief lull in her tirade, he slips outside for a sneaky cigarette with nurse Matt. Meanwhile fellow nurses Clare and Margaret enjoy a gossip about the guests and Sarah's imminent arrival. Sarah hasn't been home since her mum died two years ago and everyone wonders why... not least her sister Anna. Little does she know that Sarah hides a painful secret - she caught Anna's husband Tom in bed with one of the nurses, Fiona. And she hasn't been able to face any of them since. Just as Sarah enters the church, Fiona takes her seat. There's no time for trouble as the young bride Claudie, 30 years George's junior, makes her breath-taking entrance. At the wedding reception, chemistry ignites between Rick and Clare who share a brief kiss. Meanwhile, George makes a shocking announcement - he's retiring and moving to Malta with wife Claudie, leaving pregnant Anna and Sarah with a struggling business, one vet down, one vet defecting to the local opposition and a list of operations as long as their arm. George's revelation is enough to send Anna into labour. Anna and Tom race to the hospital, leaving Sarah in charge of the practice and their unruly kids. Anna gives birth to a girl who she names after her mother, Imogen. But George drops another shocking bombshell - they've re-mortgaged the house by £200,000. This leaves Sarah with no option but to muck in at the Chase. After a heated discussion, Fiona and Sarah make amends. Fiona reveals she has a son Theo from a previous failed relationship but little does Sarah know that the child is Tom's. Sarah's astonished when David turns up, begging her to come home, but she reveals she is home. Elsewhere, Tom's late on Theo's monthly payment. Fiona threatens to reveal all if he doesn't cough up soon...

It's Sarah's first day in the practice and just the thought of it is giving her nightmares. During the morning household scrum she puts on her battle armour to face the big day - hair, make-up, suit - looking every inch the professional. But it's a costume hiding her big secret. Practice Manager Deborah isn't very welcoming and her encounter with Sarah leaves feathers severely ruffled. Sarah's first client of the day is a border collie which needs a mammary strip - a straightforward operation but tricky without an ultrasound. Fiona has the dog prepped, but when Sarah realises that the practice doesn't even have an ultrasound she freaks and walks out, heading back to David and London. Unknown to Sarah, her sly ex appears to be entertaining another woman. Anna is furious and bombards Sarah with some hard home truths and accuses her of constantly running away. Anna drops the shocking bombshell that their mother used to run away and cheated on their father, George. Furious and cornered, Sarah finally makes her big confession, "I'm not a vet any more. I gave it up two and a half years ago. I lost my confidence. I lost a dog... the blood kept on coming." Anna is shocked into silence. At the front desk, Deborah's dealing with the angry collie owner. It's Sarah's old flame, local farmer, Adrian Huby. He's delighted to see her again, but Sarah's intent on getting back to London. On the way home, she's haunted by her memories and decides to face her inner demons. Determined to confront the past head on, she returns to the practice to operate on Adrian's collie. It's touch and go for a while but after a tense two-hour operation, the dog pulls through. Eager to make the practice a success, Sarah sells her car to pay for the ultrasound equipment. She also calls David to tell him it's over once and for all. George and Claudie's return stuns Sarah and Anna. It transpires they've been stuck in Liverpool for two days as George's passport was out of date. George confides to Sarah that he's not ready to leave Oxley. Elsewhere, a feline client forces Rick and Clare to take a step closer. Meanwhile, Tom's secret is spiralling out of control as he struggles to meet Fiona's demands. In her stalker style, Fiona confides she wants Tom to be a proper father to Theo, and that their night of passion wasn't a mistake - she chose him.

The staff are stunned by the death of a loved colleague. Anna contemplates life as a single mother while Sarah must give an answer to Adrian's proposal. The sisters are infuriated by the arrival of Claudie's sister Paula, and the contents of her beauty salon. There are other new arrivals in Oxley as both Fiona's father and Montgomery's younger brother appear to have an interest in the Williams family. But nothing can prepare them for the final revelation of the day, as the police come knocking at the door.

As the investigation into George's murder begins, Anna and Sarah are distracted by the possibility of losing everything to their stepmother. The atmosphere at The Chase becomes strained, and police, poodles and pamper packs culminate in a shock resignation. With morale at an all-time low, the staff look forward to attending the Montgomery Estate ball, where Anna finds an unlikely prince charming.

It's the morning after the ball and Anna is nowhere to be found. Wondering where she is, Tom takes matters into his own hands. Just as it seems they might be reconciled, Fiona strikes again. Sparks fly, and Anna's response to Tom's infidelity is finally made clear. The practice is in chaos with Margaret on reception and Paula's clients taking over, plus Claudie's brother Liam and his dog Stan. Anna finds comfort from a surprising source.

Deborah is back at work and enforcing a tough new regime. Faced with pedometers and mission statements, Clare and Rick are feeling the strain. Matt saves the day for Anna as he covertly stops Claudie making more changes to the house.

The Chase is bursting with new life as an emergency caesarean brings forth a yapping litter of Labrador pups. A life or death situation leaves Sarah's future hanging in the balance. Adrian, Anna and Sebastian try to put the pieces back together, but with emotions running high, are the right people left keeping the right secrets?

With Adrian and Sarah back from honeymoon, Anna is quick to ensure her betrayal of Sarah's confidence is kept secret. She is distracted by the arrival of Fiona however, who is requesting a reference. Liam is questioned by the police about George's death. Still convinced that Fiona is responsible for her father's murder, Sarah decides to take her cousin on once and for all, with terrifying consequences.

Tom is reeling from Fiona's confession and the realisation he is again embroiled in her life. Meanwhile, the local battle of the bands leaves Matt with a tricky dilemma and he and Anna are forced to consider their relationship. Sarah turns to Sebastian for support when she discovers Adrian knows the truth about her fertility problems and that Anna betrayed her trust.

There's excitement at The Chase as Tom treats a lion cub on the premises. Anna contemplates her new relationship with Matt, while Sarah agonises over her one-night stand with Sebastian. Claudie is facing sentencing for her fraud conviction and is panicked at the possibility of being sent to jail. A quick earner for Liam has dangerous and expensive ramifications.

Deborah is in her element as she moonlights as William Montgomery's PA. As their friendly rapport develops, Deborah wonders if their relationship could become something other than professional. Margaret's internet dating gets her involved with a local hunt saboteur. Rick oversteps the mark with his jealousy and lashes out at Clare. Could this finally spell the end of their affair?

Tempers become heated at The Chase as Deborah fires Clare while Rick stands helplessly by. Anna and Sarah move from one crisis to the next as the mediation over George’s estate leaves Claudie holding all the cards. Tom, desperate to escape Fiona's mind games, makes a last-ditch attempt to persuade Anna to move to Botswana. Rick is devastated to see Clare with a mystery man.

Terrified that Fiona will find out about his move to Botswana, Tom is forced to make promises he can't keep. Matt is devastated that Anna is leaving The Chase, while Rick and Clare suffer yet another set back in their relationship. Frank's concern for Fiona makes it even more difficult for Tom to juggle the women in his life, leading to a startling discovery for Anna.

The investigation into George's murder gathers pace and Tom is desperate to get Anna away before Fiona implicates him. Matt is determined to change Anna's mind while Clare is surprised by an unexpected guest. Frank reveals the truth behind his affair with Anna's mother, but his new relationship with his daughter is curtailed by a confrontation with Fiona.