026: 'Time Bomb'

Sergeant Stone and P.C. Ben Gayle race to the offices of a high profile company where a letter bomb has just been delivered, addressed to the manager, Alan Cooper. They are greeted by Alan, who leads them to his terrified PA Dani Foster, who is holding the package.

As Ben gets everyone out of the office, Stone tries to calm Dani down, but she panics and throws the package on the floor where it explodes and covers her in a white powder. Stone has no choice but to seal the room, all the while reassuring her, through an office intercom. After the powder has been tested and results show it was non-toxic, Stone lets a distressed Dani out and she runs into Alan's arms.

D.C. Grace Dasari arrives on the scene and questions Alan in front of his worried pregnant wife, Lisa and daughter. Alan is confident it was simply a hoax, but Grace is concerned it's the beginning of something sinister. Alan's brother and colleague, David arrives to take Lisa home while Grace questions Alan further.

As the case continues, officers realise that the package was delivered by regular courier, Andrew Stevens, who Alan threw out of the building a few days before after he harassed Dani. Stone and Ben eventually arrest him, but Andrew insists he had nothing to do with the bomb.

The investigation takes a shocking twist when Stone discovers bomb making equipment in David's home and finds out from David's mother that Alan had recently sacked his brother: David clearly has motive and is a man on the edge.

Stone and Grace trace David to a local park and find him sitting on a bench with a bag, clearly distressed. Grace ignores the commands from D.I. Neil Manson not to go near David and gently approaches him. David explains that he's furious with his brother who has everything: a job, a wife and children and yet he's gambling it all for an affair he's having with Dani.

Grace checks his bag, which is empty but David tells her that he's sent a package to Alan's home: a package that will cause all of the family pain…