Police dogs Meg and Thor are reunited with their handler Martin after he broke his leg. They track a mysterious BMW with suspected links to drug dealing.

In Liverpool, new recruit Chico finds a huge stash of cannabis up an alleyway, helping his handler PC Bartley disrupt a major drug operation.

In Yorkshire, Alsatian Thor joins a firearms unit and storms a derelict building. Meanwhile, sniffer dog Meg raids a flat with possible drug dealing links.

In Yorkshire, PC Fletcher's dog Patto has been injured chasing a burglar. In Merseyside, PC Harris and his dog Kane are trying to track down the driver of a stolen car.

PC Bartley reminisces about his first dog, who was killed in action chasing a gang of burglars. Sniffer dog Lucy is called into action when a driver is stopped.

PC Gayles and his dog Thor are on the hunt for evidence to convict mobile phone thieves. In Glasgow, sniffer dog Eddie carries out his first search for a gun.

In Merseyside PC Bartley and his dog Chico are involved in a high-speed car chase. And new explosives detection dog Pip is at Aston Villa football ground.

Devastating news about PC McIntyre's Alsatian Rudi jeopardizes their future together. And can sniffer dog Meg show her skills on a suspected drug dealer's car?

As police surround a flat where a gunman is thought to be hiding, PC Fletcher's firearms support dog, Patto, faces a dangerous situation.