When Ken and Lorna collect their daughter Rachel from the airport, they're horrified to learn that she's returned from her gap year with more than just a henna tattoo and braids in her hair.
At the arrival gate, she promptly introduces them to her new husband, Cuckoo - the squared-jawed, self-appointed "spiritual ninja" who is now their son-in-law. Cuckoo is every parent's worst nightmare - a slacker full of outlandish, New Age ideas.
Ken and Lorna have no choice but to welcome him into their family home - and if every Englishman's home is his castle, then this hippie has stormed Ken's fortress and plundered everything, most unforgivably, his princess.
Cuckoo Ended after Season 5
BBC THREE aired the final episode on Thursday 10th January 2019