Can't remember how much happened in the last 10 minutes, but , Julie who Maloney had struck up an affair with had been paid to get information from him, the boy was kidnapped just after his father was released from prison so he was suspected. Maloney sussed her out and checked her mobile phone, that girl at the office who gets all the info gave an adress of a number frequently called. When Rose & Maloney went to it the boys original (and since discovered step ) father answered. Pulled a gun on them, Max jumps throught the window, Maloney grabs gun. Max rescues brother. Step father admits to faking his own death and using a recording of Marcus's voice during the killing. Meanwhile Rose it at her new flat (wired) talks to Marcus about the killings, he denies it but admits to supplying some thugs with firelighters to burn down the flats where 7 refugees died. Smug as he likes Marcus and his barrister are summing up with R&M and their boss about how innocent he is and Rose leaves the tape running with him admitting his part in the fire. They invite the old sergeant in (Grover?) and he arressts Marcus for the murders. Max & boy and Grandma presumably live happily ever after. Rose decides to move back in with Maloney and gives him a smacker on the lips in the office having both quipped about liking to live with each. I thought insinuating that this is going to tease along for a while.
Hope this helps.