Dan returns to Dublin and looks to make up with Susie, but soon discovers she has gone to Thailand. Cathy prescribes penicillin to a patient, not knowing the serious effect the drug will have on them.

Clodagh, the new GP, has a bad start to her day when she knocks Ed over. Her day goes from bad to worse when she suspects a patient has an ectopic pregnancy, but is overruled by Cathy's father, Mr O'Callaghan.

Things are hotting up as affairs start rising to the surface. Paul tells Keelin he knows about her and Ed and begs her not to say anything to Yvonne about his carry on at the stag party. Meanwhile, Cathy tells Ed she might be pregnant and in turn Ed tells Keelin the news, who lets a congratulations slip to Cathy! Meanwhile, Yvonne hears Keelin and Paul fighting about his stag night antics and loses her temper with Keelin and tells her she doesn't want her to be her bridesmaid any more.

Dermot asks Fiona to join him for lunch. Cathy is interested in buying next door and goes to her Dad in the hope of interesting him in investing.

Ed finds Cathy's pills in her drawer and concludes that they have different ideas about wanting a family. Cathy visits the bank and realises that they will have to let staff go if they are to service the loan that she hopes to get to cover her dad's share.

Ed wakes up in Patrick's flat. He walks home, hungover and meets Cathy out for a run but she ignores him. Cathy confides in Áine that she and Ed are having problems.

Cathy wakes up to see Dan in the next room and wonders what happened the night before. Ed meanwhile wakes up at Patrick's who tells him that he should go home. Dan sees a former patient of Ed's for a cosmetic consultation and suspects she has a thyroid problem.