When her mother Margaret announces her intention to marry widower David,Maddy does not share the rest of the family's enthusiasm,especially as he has had four previous wives and the happy couple met at the last one's funeral. Being a bridesmaid in a vast fluffy dress does not appeal either but when Margaret seems to have cold feet Maddy talks her round into tying the knot. Katy manages to lose her grandma's car and get it wheel-clamped whilst Dan defeats the school bully by telling him he fancies him.
When a client of Jim's goes bankrupt,owing him thousands,he asks Roger,the lawyer from next door for legal advice and ends up getting billed for his services. Meanwhile Amanda,a woman Jim has met on the Internet and is obsessed with him,shows up and kisses him in front of Danny. Hearing the parents discuss how to deal with Roger the kids assume they are getting divorced but when the matter is cleared up they combine to put Amanda off.
Maddy feels the rest of the family are keeping secrets from her after she recently embarrassed them in public. They claim that she cannot stop interfering so she agrees to back off from their lives. Inevitably they find themselves in all sorts of trouble without her interference. Jim becomes addicted to caffeine after he is given a coffee vending machine and needs Maddy's help to break the habit.
Ted's dad Robbie gives him a snake,of which the rest of the family live in fear. The snake escapes whilst Maddy and Jim are next door having dinner with the Weavers who are experiencing marital problems and the kids trash the house trying to find it,claiming that they were burgled. By this time Maddy is offering the Weavers advice on how to settle their differences - differences which are only resolved when the Weavers see how argumentative Maddy and Jim are by comparison.
Maddy feels Jim should express his feelings more,rather than remain silent on things,though when Ted airs Francophobic views to Danny's French exchange student Anne-Marie,she is annoyed - even though it turns out that Anne-Marie is from Cornwall. When Jim takes Maddy at her word,however,she rather wishes he hadn't as he ends up fighting in the street with Roger.
Ted is shocked by Maddy's handling of the family finances and takes over their control whilst Danny befriends a weird kid called Russell purely to get near his fit sister, only to discover that Russell is hanging out with him to get a date with Katy. Jim hears that an old friend has died, causing Maddy to reflect on the fact that he has virtually no social circle but her efforts to remedy the matter end in a party where the Weavers argue as usual and Ted sells the house to a stranger to relieve the financial burden. At least Maddy's attempt to get Jim on a play-date ...
The family's computer rashes,leaving them without an Internet connection and,after spending a fortune on the help-line,they learn that the guarantee has expired. Maddy takes Rosie to a nursery where the yummy mummies are not amused by her jokes though Jim is a hit with them. Unfortunately Rosie catches a cold which spreads to the rest of the family. Will Maddy miss her night of pampering at a spa as a result of having to nurse them?
When Jim's children get the chance to spend summer in New York with their glamorous mother Christine, Maddy fears they will not want to return and sets out to prove her parenting skills to win over them. Although she fails she at least feels better when the Weavers argue in front of her and even better when Christine rings to say the trip is off,especially as the kids say they always knew their mother was unreliable. Ultimately what is most important to them about Maddy is that she is "always there."