When DC Chris Skelton opens CID's post and discovers a human hand, DCI Gene Hunt and his team find they have a murder to solve. The only defining feature on the severed limb is a strange burn mark and DI Alex Drake and the team discover there have been a string of single women murdered across the country, each left with the same crescent moon shaped burn. It seems all the women had one thing in common; they were members of the Crescent Moon Dating Agency. When Alex registers with the agency and gets nowhere she decides to take matters into her own hands and invents Speed Dating, much to the distaste of the agencies owner, Elaine Downing. As Luigi's fills up Alex does her best to play the lonely single woman. DI Ray Carling and Chris find themselves an attractive pair of twins to charm, while Gene on the other hand is struggling to attract anyone of the opposite sex. Meanwhile, WPC Shaz Granger, feeling let down by the force, has handed in her notice. However, Gene manages to persuade her to take on one final operation and go undercover to catch the man they believe is the killer. But as Shaz puts herself in the firing line it seems this may be her last sting in more ways than one... Also, Alex is still working to discover the truth behind Sam Tyler's death after her tip off from Jim Keats that Gene had something to do with it. But when Gene discovers what she's up to he can't help but intervene.