Mayo is a master of crime-solving and a man obsessed with figuring things out, whether it's how gadgets work or who committed the latest murder on his patch. Mayo and his team – the sexy DS Alex Jones, with whom Mayo conducts a tantalising will they/won't they flirtation, cocky laddish DC Martin Kite and nerdy Scene of Crime Officer Harriet 'Anorak' Tate – are a formidable crime-fighting force.
Mayo's strength is his somewhat pedantic attention to detail, alleviated only by his black humour. Alex takes the instinctive approach, which infuriates Mayo, especially when she is right. Often. Anorak enjoys the laborious nit-picking process of sifting through the evidence at the crime scene, a hair here, a speck there, and Kite is an enthusiastic and vain 'puppy' whose tenaciousness contributes to solving the cases.
With a clever and intriguing 'whodunnit' at the core of every episode, the murky world of crime-solving has never been so entertaining.
Alex is offered a promotion in London, and with Mayo refusing to admit his feelings for her, she decides to tell him she has accepted it. The pair work on what could be their last case together when a cleaner is asphyxiated with a duster, and the investigation leads them to a local politician whose house the murdered woman cleaned.