So Long Baby

Robbie Ross clocks off, walks home, and finds a baby gurgling on a doorstep. Nobody answers the bell, so he goes round the back, finds a French window wide open and a man dead in a pool of blood. The baby is fine, which is the first surprise of the night and not the last. In one walk home, Ross has picked up a murder and an abandoned infant. And the obvious question is whether the two belong together.

The dead man is Jack Revie, wealthy and, by all accounts, a philanderer. His wife Joan says she was out visiting his mistress. A young woman called Lisa Corrie turns up claiming the baby is hers and Jack was the father. Jack's son Jamie was in the house at the time but too stoned to be reliable. Half a million pounds has gone from Jack's account, and his dodgy friend Davy Kincaid is on the run. It's the sort of case that makes a detective long for a quiet paperwork day.

Glenn Chandler and Morag Fullarton wrote it, with Fullarton directing. Michelle Fairley brings steel to Joan Revie, Hugo Speer is Ron Cassidy, Stuart Martin is Jamie, Iain De Caestecker is Davy Kincaid, Kirsty Strain is Lisa Corrie and Donna Giffen is Pilar Sanchez. John Michie's Ross has to solve it before his holiday, which seems unlikely to happen on schedule.

The episode juggles a missing fortune and a disputed baby while the dead man's life keeps unraveling in front of the team, and it keeps all the balls in the air. The baby on the doorstep is the best kind of hook: it looks like sentiment, and it turns out to be a piece of evidence. Nothing about the case is as cosy as the opening image, and the show knows it. Ross's walk home was never going to be simple.