'Tears For Souvenirs'

Jimmi enjoys a loved up picnic with Cerys but the moment is ruined when he's called upon by Rob to help with the investigation.

Rob heads out to work, unaware that he's forgotten his and Karen's wedding anniversary.

An argument erupts when Karen goes to meet Rob at work but this soon dissolves into a passionate embrace back at the house. The amorous couple are interrupted by a surprise anniversary party organised by Cherry and Simon.

Both Imogen and Jack are appalled by their parent's antics but Karen and Rob are content to slow dance and celebrate their 20 years of marriage.

Meanwhile, DI Driver calls on all units to a drugs bust on the flat of Jason Merrick (22). The bust is ruined when an elderly couple, Bill and Mavis Bateson (70s) inadvertently arrive on the scene and alert Jason to the Police presence.

As Rob tries to pacify the perturbed couple, especially Mavis who has dementia, Driver informs him that the bust was fruitless as Jason had plenty of time to ditch any incriminating evidence. Rob manages to antagonise Driver and is left to babysit the elderly couple.

After dropping the couple home Rob's suspicions are aroused by Bill's obvious attempts to get rid of him but when Rob tries to talk to Driver back at the station he's dismissed.

The truth starts to come out when Rob is called out to an incident. He sees Mavis alone and in her confused state she reveals that Bill has left with their 'grandson' Jason who they were visiting this morning.

Once again, Rob tries to speak to Driver about the investigation but is told to keep his nose out, so he takes matters into his own hands. Mavis leads Rob to a warehouse and when Rob enters, Jason is making a quick escape whilst Bill is unconscious on the floor.

Whilst Bill recovers in hospital; Rob shows Driver the bag of drugs that was uncovered from Bill, who was carrying heroin in condoms in his stomach for his grandson. Rob is disgusted by Driver's cold attitude to the couple, and manages to question Bill's motives before Driver. Bill reveals he was desperate for money and their grandson Jason offered a potential way out.

Rob manages to persuade Bill to cooperate and give a full statement against Jason but Driver is angry Rob has gone in all guns blazing and offered Bill a deal. She warns Rob to never cross her again and Rob is left to lick his wounds.