Larry has moved into the flat but his slovenly ways and habit of nicking the others' food are not exactly endearing him as a house-mate. Then Mildred comes up with an excellent idea. Clear out the attic and let him take it as his room. George was spending too much time up there anyway.
Robin has taken his new girl-friend Angie out on a couple of dates but now he hopes to bring her back to the flat to have his wicked way with her. However, not only is she against sex before marriage but she is also an old school-friend of Chrissy, who takes a very protective attitude towards her.
There is a formal dinner-dance at the firm where Jo and Chrissy work but Chrissy's prospective dance partner has injured himself so Robin, after a few dance lessons from Mildred,becomes her partner instead. He tells people that he is a brain surgeon but ultimately comes unstuck.
There's a mouse loose about the house and, though Larry kills it,Robin wants him to keep quiet about it as the girls are scared of the mouse and Robin can exploit their fear to get closer to Chrissy. George also wants to keep up the pretence that the mouse is still around to ward off a visit from Mildred's family, but it is ultimately Robin who gets trapped.
An anonymous admirer is sending Chrissy flowers and chocolates,which she gives to Mildred. Mildred tries to make George jealous by pretending that in fact she is the one with the secret admirer. An old flame of Chrissy's,who is not the sender but is keen to see her again turns up at the house and is mistaken for Mildred's lover by George.
Whilst Mildred is visiting family George tries to evict the four flat-mates by saying that he needs the flat for his - non-existent - aged mother. The truth is that he wants to turn the existing flat into bed-sits so that he can charge more money from individual tenants but his plan is thwarted when Mildred returns.
When Robin is rushed to hospital during a poker game he asks Chrissy to take his place. This is a very bad idea as she has not got a clue as to how to play and puts the rent money at risk. George steals from Mildred in order to get the stake money to take part in the game and pays the price.