Sue Vertue

It is the acclaimed modern retelling of Arthur Conan Doyle's classic stories. But now, our heroes find themselves in 1890s London.

Season four begins with the mercurial Sherlock Holmes, back once more on British soil as Doctor Watson and his wife Mary prepare for their biggest challenge yet: becoming parents.

Late at night and a phone call that Will Not Die. You know how sometimes you can't get someone off the phone? There are too many people in this phone call. And one of them isn't really there. Meanwhile, Susan is worried she's turning into an emotional tent; she and Steve are now well and truly an item – so why is he dreaming about being executed by a method Never Before Seen on British Television - and chased by a foetus with an axe?

One bar, three different points of view, the same nine and a half minutes. Susan and Steve are now pregnant (well, mostly Susan); Patrick and Sally are discussing commitment (well, mostly Sally) and there's this guy called Oliver who has a blind date with Jane. But is his job going to be a problem? Meanwhile, in the skies above an Aegean island, terrible danger grows. Featuring hot girl on girl action with Gina Bellman and Sarah Alexander.

The night before the birth of his first child, Steve is visited by an old friend. Or possibly an old maths teacher…Meanwhile, someone is trying to get into Jane's flat, and an extraordinary secret is lurking inside the cupboard of Patrick's love.

Sally is having a drink with a complete oaf called Brian. She spots Patrick with a bunch of business cronies and begs him to rescue her, which he does in true tripod style. Soon they are drinking to Code Red and wondering whether they should have got indelicate together. The next day, Sally decides they should do it - now, a one-time-only offer. He's got the builders in, her flatmate's at home with 'flu; but she has the key to Susan's flat and arranges...

Three eggs, three women, three possibilities. Now Sally's blurted out how she feels to Patrick and has convinced herself it's not meant to be. More importantly, she really, really doesn't want to produce a bald, noisy thing that will destroy her life - and decides to use Jane and Susan as a pregnancy control test, which leads to some unexpected revelations.

Jane finds herself competing with the Supreme Being of the Universe. She feels it isn't fair on either of them. Jeff has been going out with Julia for some time. But then the disconcertingly lovely Wilma propositions him in the stationery cupboard. Meanwhile Jane meets and quickly unnerves the ruggedly handsome James under similar circumstances.

Steve and his best friend, Jeff, head for the wine bar where Steve has decided he is going to dump his longstanding girlfriend once and for all. Meanwhile Susan and her best friend, Sally, are heading towards the same destination with equal determination. Is this the evening when 'he' is going to propose? But all is not as it seems.

Steve has been having problems with being witty and eloquent on the phone to Susan. Susan invites him 'round for supper at her place. As Jeff expounds on "the sock gap" and offers advice on foreplay and his theory on celebrity marriages, he has no idea Susan can overhear everything. Meanwhile, Patrick invites Sally on a date to a motor show. Elsewhere, to everyone's surprise, Jane materializes with Howard, a particularly good-looking young man.