A skeleton uncovered in the foundations of a swimming pool is identified as Cheryl - a young, pretty lottery winner reported missing 17 years ago. UCOS' prime suspects are her quiz teammates, who won their lucky windfall as part of a syndicate. But while some have put their money to good use, the victim's boyfriend has fallen on hard times, and the media remain convinced he is the prime suspect in her cuddle.
As allegations of affairs, fights and betrayal begin to surface, the team are left to ponder whether money really is the root of all evil.
Sasha is set for a night in studying, but the boys have different plans and plot to set her up with Fiona's colleague Adam.
New Tricks follows the work of the Metropolitan Police Service's Unsolved Crime and Open Case Squad (UCOS). Led by Detective Superintendent Sandra Pullman, it is made up of retired police officers who have been recruited to reinvestigate unsolved crimes.
The series title is taken from the popular expression "You can't teach an old dog new tricks". The "old dogs" are successful in adapting their skills and experience to modern policing, with their knowledge of past cases proving especially useful.