Maria and Richard have bought a larger house than they can afford, and are starting to struggle under the weight of debt. The house is in need of maintenance work with a quote from a builders on replacing the roof, and with little potential for selling their home, they discuss a possible loan. Richard heads to the bank to enquire about a loan, but is rejected due to outstanding loans and his current mortgate situation. Meanwhile, Maria discusses things with her mother who suggests a lodger may be in order. Advertising in a local shop, Maria soon has a viewer, student Paul who agrees to take the room despite its poor condition. However, a second viewer and also a student, Ruby, arrives leaving Maria feeling sorry for her situation and agreeing to take her as a second lodger, meaning Richard has a surprise upon returning home from work.
Paul and Ruby have now been in the house for a few weeks, and having them around is making Richard feel old while Maria is starting to feel motherly. Renovations on the house have also began with the incoming money, with Maria, Paul and Ruby taking on the decorating themselves much to Richard's dismay. Paul admits later to Maria that he is having problems at university getting the work done, as well as having little money and now late with his rent, so Maria arranges for him to do the painting in lieu. This however causes problems with Maria and Richard facing an argument just before bed. Paul takes to asking Richard for help with an assignment which Maria suggests he will end up doing. Paul has managed to get a job in the student union bar, as well as completes the decorating of the first room though Maria warns him that he can't depend on them to always help him out of every problem.
Maria has a job covering a maternity leave for a local newspaper and will be writing a feminism column. Ruby is also struggling for money, while Paul suggests a car boot sale to sell some belongings including a number of Maria's stored in the attic which are taking up space. Maria also takes to working late at night, leaving Richard feeling rejected and lacking attention. Paul and Ruby find some old Dinky cars in the attic, which Maria says they can sell while writing her article, however they belong to Richard leading Maria to race to the car boot to prevent them being sold. However, it is too late and Maria resolves to keeping Richard from finding out until she can get them back. Handling the dealer that bought them, she pays a price for the cars before returning to the house to tell Richard what happened.
Maria and Richard's wedding anniversary is coming up, though Maria is expecting it to be predictable as usual while talking to Ruby. Ruby sets about asking Richard's friend Amy to persuade him to do something different. Richard arranges a trip for Maria, leaving Ruby and Paul at home who plan on having a party. At the restaurant, Maria and Richard wonder how the party is going and decide to drop by, where Richard finds a girl crying while stuck in his bedroom having been trapped by Paul's DJ equipment, who is upset at her boyfriend who called her boring. Richard offers advice on being more spontaneous as a way to fix her relationship. Meanwhile, Maria is enjoying herself dancing and gets invited out on a date as Richard prepares to take her back to the hotel. The following day, Ruby and Paul give their present - a lamp - to replace a lamp broken by Richard at the party.
Ruby is away with a friend named Daniel leading to jealousy from Paul, while Richard has taken to digging in the garden leading to him having a bad back. Richard is also happy to see Ruby getting involved with someone else rather than Paul, though he has to contend with neighbour Amy encouraging Paul to continue his pursuit of Ruby. In the late evening, Paul and his friend Pete create pavement art in time for Ruby to come home though are left disappointed when she misses the last train back for a party, and the art is destroyed by a downpour. Ruby eventually returns the following day, and Paul is pleased when he finds Daniel is leaving for America to meet up with his partner, though he pulls out of revealing his feelings. Amy is informed on the latest developments by Maria who suggests that a picture she took of the pavement art may be used to push Ruby and Paul together in the future.
Ruby is on a healthy diet, while Richard is also questioning his weight. Paul is planning on going in for a half-marathon, though finds competition from Richard who also decides to enter. Alice and Maria wager on whether Richard will make it to the finish line, as do Ruby and Paul. Richard however still remains confident and fitter than he has in years. As the end of term approaches, Richard and Maria begin to wonder what the future will be with Ruby and Paul staying at the house, though both are still keen on having them around. During the marathon, both Paul and Richard make it to where Ruby and Maria are watching. After visiting the pub, they head to the finish line where they soon find Richard crossing the line. They later find Paul who had to quit the race with an injured ankle. The four go out for an evening meal which Maria pays for with her bet winnings, however Richard ends up falling asleep before dessert.
Zeppo, one of Ruby's guinea pigs is not feeling well, while Richard has been skip foraging as part of a drive to prevent unnecessary waste. Contemplating skips, Richard and Maria decide to hire one to clean out various areas of the house and garden. As Ruby and Paul get into a debate about the merits of going out together, Paul discovers that Ruby is an Arsenal fan. He does however set about proving that he is not selfish and can do things for other people. While loading items into the skip, Richard is angered to learn that his stepladder has been stolen. Maria also suggests Paul should sell his DJ equipment which is still cluttering up the hall. While Paul is cleaning the guinea pig cage, Zeppo goes missing and believes he has ended up in the skip which leaves Richard and Paul digging around the skip in the middle of the night. He eventually comes clean and discovers that Ruby took Zeppo out of the cage, and has given birth to babies.
Richard is not feeling well, and is being a particularly difficult patient. Paul and Ruby have taken to going out together, though Richard is wondering how long it will last. Ruby soon ends up catching the cold, which leads to jealousy from Richard when she gets Lucozade bought for her by Paul. Feeling confident that he won't catch the cold, Paul soon finds he has it. Losing his voice, he plans on cancelling a gig he had scheduled though Maria manages to talk to the now-better Richard to stand in as the record announcer. At the event, Richard's announcing gets off to a rocky start but ends up going well in the end despite him making somewhat of a prat of himself as he even gets an offer from the nightclub owner. Maria end the night by passing out from too much drink, and the following morning wakes up feeling worse for wear.
Maria is struggling with writers block as a deadline for her article approaches. Ruby attempts to cheer her up by inviting her out for a drink, while Amy suggests a shopping trip would resolve the issue. Paul can only come up with plagarising someone else, while Richard decides on attempting to make her laugh. Ruby is also struggling with ideas from her dissertation, as she is unable to convince her tutor on any of her plans. Stuck watching daytime television while eating chocolate biscuits with Paul, Maria and Ruby conjure up the idea of writing about supermodels and the way they are perceived by society. Richard also tries to help out by purchasing a word processor for Maria, who finds getting to grips with it somewhat difficult. When she believes she has lost her finished article by accidentally deleting it, Maria contemplates whether it is the end of her writing career.
Maria's flighty friend Ellen is due to turn up to stay for a couple of days, leaving Richard less than thrilled as she also has a snobby attitude. Ellen arrives and discusses her marital problems back at home, as she reveals she is going through the menopause despite being relatively young still, though her husband wants more children. With the talk of children, Maria and Richard also consider their chances of becoming parents. Ellen questions the suitability of Paul and Ruby seeing each other under the same roof, while Richard also attempts to deal with who he believes to be Ellen's husband, though instead it is a university housing inspector coming to check up on Paul and Ruby's living situation. Ellen eventually returns home to fix her relationship problems, and is particuarly pleased with Richard with his attempts to stand up for her.
Paul has lost his job at the University bar, and Ruby offers him money to cover the rent. Paul wonders about the future and was hoping to move in together with Ruby. Ruby however believes he is trying to move too fast, when he issues an ultimatum on working out what she wants as he plans on moving out whatever happens. While Ruby is discussing horoscopes with Richard and Maria, Paul reveals he is getting rid of his DJ equipment from the hall. Ruby discusses her problem with a friend, but doesn't get very far, so decides on seeing a fortune-teller. Heading to the fortune-teller with Ruby, Maria is told that she is pregnant and Ruby is told that the answer is within her. Back at home, Ruby sits down with Paul and says that she wants to carry on as they are as Paul comes to realise his own childishness over the situation.
Maria is contemplating her next steps, and wonders if she will have to ask one of Paul or Ruby to move out. The pair also have their own problem, which looks like one of them moving back into the student halls, with Paul losing out though he reveals he was previously kicked out of the halls. Maria eventually tells Richard the news, who is delighted by the news, and agrees to be the one to tell Paul and Ruby the situation. When Richard fails to tell Ruby and Paul, they begin to believe she has a terminal illness when she begins to feel slightly unwell. Ruby heads to Amy's to try to find out what is going on, though she also refuses to reveal all. Maria eventually sorts the situation by telling Ruby. Ruby in turn puts a proposition to Maria that the pair move in together, and be able to stay in the house despite it still being a little cramped.