'Who killed 14-year-old May Queen Hattie?' is the big question, hidden beneath tales of seedy peeping Toms, twisted relationships, moody teens and a broken community. But have you figured out the culprit yet?
Peter Firth's Malcolm was the obvious suspect after an intense feud with Hattie, but after killing himself midway through the series, he looks likely to be a red herring.
Could it be Seth (Tom Fisher) or Steve (Sam Spruell), the brothers who both have connections with the late girl?
Or maybe you think the sinister-looking Everett, played to creepy lip-curling perfection by Aiden Gillen, went too far with one of his sexual dalliances?
Watch a clip of the final episode of Mayday:
The other prime suspect is local copper Alan, played by Peter McDonald. He claims to have had an altercation with another girl on the day of Hattie's disappearance - is that the truth?
Is there a chance it could be someone else entirely? Has Sophie Okonedo's Fiona been hiding something? Does Hattie's rebellious sister Caitlin (Leila Mimmack) have a dark secret? And is there any chance that moody teen Linus (Max Fowler) did the crime?
The final episode of Mayday airs tonight (March 7) at 9pm on BBC One.
Who do you think killed Hattie? Have you been impressed by Mayday? Share your views below!