Twenty-six-year-old Michael is determined to find someone to love, but is struggling to hold down a relationship. Despite having had 17 girlfriends in the past, some of whom lasted only a few days, his autism means that even holding a conversation with a girl can be a huge challenge.
He goes to a speed-dating evening and then, after a pep talk from his mum, he pulls out all the stops on a blind date with Helen.
Twenty-one-year-old Brent, from Plymouth, has been single for nearly a year since coming out of a long-term relationship. Meeting girls can be hard when he doesn't know what might come out of his mouth on a date. Brent's Tourette's syndrome includes shouting, swearing and involuntary movements, but dating can help with his condition. He goes on a date with Lizzie and they then go snow-boarding.
Sarah from Hertfordshire was 18 when she suffered a stroke during an English lesson. Three and a half years later, she has a condition called expressive aphasia which makes communication extremely difficult. Any kind of social interaction is a huge challenge, let alone dating. Sarah goes boating with city worker Gary; could he be the man she's been looking for?
Extreme sports enthusiast 34-year-old Samantha has it all - amazing friends, a beautiful home, and even a PhD in psychology. The only thing eluding her is love.
Attractive, articulate and bright, Sam should be fending off suitors, but Sam has achondroplasia, the most common type of dwarfism, and being 3 foot 10 tends to attract all the wrong kind of attention. She's looking for someone as gutsy as she is - will James from New Zealand rise to the challenge, or is rocker Colin more her type?
Ray is 49; an office-worker who has a learning disability, Ray's heart was broken three years ago when his fiancee Lolita left him. He's decided it's time to meet someone new, even though moving on means finding love through the dating agency that Lolita runs.
But Lolita is feeling emotional about Ray's return to the dating game and thinks she might want him back.
Thirty-year-old Steve is worried that his facial disfigurement - Crouzon Syndrome - may put off potential girlfriends. He's ecstatic when he gets a date, but devastated when she cancels on him the day they were meant to meet.
But when he finally does get a date, with fellow music-lover Ellie, can he conquer his nerves?
This time the Undateables include Kate, an incurable romantic, and Damian, whose dream date is a moonlit picnic in the park.
Amateur poet Kate is 29-years-old and has Down's Syndrome. When not working, Kate writes verse or watches rom coms. She dreams of finding her perfect man and future husband.
Having been single for nine years, Kate decides that it's time to turn to dating agency Stars in the Sky for help. The agency sets her up on a blind date with 32-year-old year old Simon, and they visit a maze in Ross-on-Wye. The date goes well, and they arrange to meet for a second time.
Damian has albinism and must spend much of his time indoors. He has been single for four years.
Oliver is an artist who paints romantic scenes of his own imaginary love life. Diagnosed with autism when he was two years old, he often finds social situations difficult.
When Oliver meets Amy at a disco, they decide to go on a date together and he ends up plucking up the courage to ask her to be his girlfriend. Are Oliver's single days over?
Heather has severe OCD. Gareth has brittle bones and has broken his legs over 150 times. Matthew has autism. Can the three of them find partners?
Thirty-eight-year-old Heather's OCD means she cannot have any physical contact due to her fear of contamination by people's germs and hasn't invited anyone into her home for years. Heather also has Asperger's, making things such as eye-contact very hard for her. Heather goes on her first date in three years, with Peter.
Twenty-eight-year-old Gareth has osteogenesis imperfecta (OI) which makes his bones extremely brittle. He has broken his legs more than 150 times in his life, and uses a wheelchair. 'I just don't want to die a 40-year-old virgin', he says.
Gareth takes Beth on a date to a seafront restaurant, but will they hit it off?
Matthew is 20 years old and is a student at a college in Milton Keynes. He is keen on karate and indie music. Despite a busy and fulfilling life, Matthew has autism and has never had a girlfriend .
For his first ever date, Matthew takes Nicola from St Albans, who also has autism, to an Indian restaurant. Will he be able to get over the fact that she is a Peter Andre fan?
This episode revisits Richard, an amateur radio enthusiast with Asperger's, and comedian Luke, who has Tourette's.
There's also 32-year-old Shaine from Bournemouth, a prolific amateur poet with a learning disability who's written over 3000 love poems, some for complete strangers.
Sam, from Kent, is a media student and actor with Down's syndrome who's appeared in The Inbetweeners and EastEnders.
Last year, having never been on a date before, Sam fell in love with 28-year-old Jolene and, seven months on, the romance is still going strong.