Martin finds it hard to cope with being a father as he starts a new chapter in his career, which looks like will take him away from the Cornish village. Martin's relationship with Louisa becomes shaky with all the sleepless nights. Dr Di Dibbs and her husband Gavin have moved into Martin's old surgery. Martin starts to have serious doubts about the competence of Di though and ends up confronting her. Martin also has to deal with the loss of Aunt Joan.
Martin and Louisa find sleepless night taking the toll on them and tempers are frayed as they try to find ways to comfort the baby. After the baby is woken up by Buddy's barking he takes him to Aunt Ruth. Ruth has to deal with an intruder on the farm who has stolen the hub caps from her car. He ends up being revealed to be Michael Dunwich who lives with his mother on a neighbouring farm. Ruth soon realises that Michael is a bit odd and sees that he has a collection of metal objects strewn around the garden. She later sees him taking pot shots at her hubcaps. Shirley goes to see Martin to talk about the crippling stomach pains she has been suffering with and shares her fears that her son is trying to poison her. Morwenna Newcross fails to make a good impression Martin by arriving late on her first day as his new receptionist. Shirley's test results reveal that there is a large concentration of arsenic in her system. After going to the farm Dunwich, Martin finds Ruth attempting to help Shirley and Michael a gun. Penhale thinks he has been shot after a shot is fired and Martin manages to gain control of the gun. Martin notices a strange smell from some old wallpaper in the house and ends up realising the copper arsenate from the old wallpaper which Michael had started to strip had produced deadly fumes and caused Shirley’s illness.
It’s Portwenn Fun Day and the village is really looking forward to major fund raising event. PC Penhale enjoys rallying the runners and creating more support. There ends up being a rivalry between Bert Large and Mark. They are both want to take advantage of the day to boost their takings by providing food for the runners and spectators. After Mark’s enterprise is closed by Martin after he diagnoses an infection which means he must not handle food, and bans him from going into the kitchen. Bert ends up seizing the chance to take over the ‘soiree’. Louisa’s mum Eleanor shows up in town unexpectedly and Louise isn't pleased to see her.
Joe Penhale gets an unexpected visitor when his ex wife Maggie shows up. After he attempts to tell her they are no longer married she wants to know why he left her. Joe soon realises that she is not well, especially after she tells him she thinks it is April 2008. He attempts to discreetly talk with Martin about her symptoms without telling him that he is talking about his ex wife. Joe is scared about loosing her again and arranges a romantic evening for them at a local restaurant. After Martin runs into them he realises what is wrong with Maggie. Eleanor meets an old school friend called Paul, a local fisherman who takes her out on a date. After Paul collapses on his boat and falls overboard, the doctor has to give mouth to mouth to resuscitate him. Morwenna shows up at work with blood dripping from her foot after standing on a nail. Martin and Louise finally come up with a name for the baby.
Joe is desperate to show Maggie that he is a changed man and that he is the macho husband she wants. Maggie plans to return to Bude after she gets the all clear though. Joe ends up resorting to desperate measures to convince her not to leave including paying people to be nasty to her so he can step in and assert his authority. Martin has to rescue the local school caretaker after he gets into trouble. Ruth finds a chest of family heirlooms as she clears out a barn at the farm. Louise isn't happy when Martin thinks about signing their son up for boarding school. After Louise finds out that Martin has set a date for their son's christening without consulting her she ends up moving out and going back to her mum's house.
Bert Large’s restaurant business is in serious financial trouble and he is also being chased by loan sharks Alastair Tonken and his son Norman. Al is not happy with his father for losing all their money. Bert thinks Al is to blame for spending too much time working for Ruth. After Ruth gives Al £800 to pay for the fencing on the farm he ends up deciding to use the money to pay back the some of the loan. Bert and Al decide to enlist the help of Joe Penhale but he informs them there is nothing he can do to help. After a row breaks out, Joe tells the loan sharks to leave the village and never come back. Eleanor comes up with a plan to improve custom at the restaurant. Louisa insists that Eleanor sees Martin after she feels unwell. Martin is planning to leave the village for good in a week’s time to resume his career as a surgeon, leaving Louisa and their son behind.