The Thames Valley Major Crime Unit investigate a tragic murder on the eve of Valentine's Day - fuelled by jealousy, anger and pride, it's a tale of love gone wrong.
A gunfight in suburban Kent leaves a victim seriously wounded and sparks a frenetic high-pressure race to hunt down the perpetrators.
An RSPCA Special Ops team investigate an international criminal puppy farming operation, and Lancashire officers prosecute an owner for animal cruelty.
The Serious Fraud Office go undercover to investigate a suspect holiday home company offering exclusive residences in the sun-drenched Caribbean.
Counter Terrorism Policing foil an extremist Islamist terror plot, and the CPS Special Crime Unit bring those responsible for a fatal crash on the M62 to justice.
Manchester police take down a gang of teen car thieves while the Serious Fraud Office unravels a 400-million-pound global fraud in the steel industry.