Jo stepped into the flat, with Atkinson close behind. She went into the first bedroom, the one with the crib in it. She started opening drawers, slamming them when she found nothing but women’s clothes, kids’ clothes, toiletries. In the box under the bed there were shells of varying sizes and colors, the larger ones with intricate, earlike curves on the inside, shining pinkly, almost glowing. Jo weighed one in her hand. It was heavy, like a rock, its edges sharp and brittle.

In the other bedroom, it seemed at first that there was even less to find, until she opened the wardrobe and pushed aside the shirts. There was a metal box, padlocked shut. For a split second she paused, considering the consequences of what she was about to do: tampering with evidence, ignoring direct orders, interfering with an investigation. Together it spelled court order, disciplinary, maybe even gross misconduct. Then she thought of Ruby’s expression in the photograph from the train station. So far away, so lost and alone. Up until recently Jo had assumed Ruby was fine, but she had to admit that it was a convenient assumption—if Ruby was fine, then Jo didn’t have to do anything. She realized now that it wasn’t just the past few months: assuming that Ruby was fine had been her default position ever since the baby was born and handed over to Marianne. Well, she couldn’t use that excuse now, or ever again. Ruby was in trouble, and the only person in a position to help was Joanna. She loved her job; she’d dedicated her life to it. But if it came to a choice, there was only one way to go. In that moment it didn’t even feel like a difficult decision.

She took a pair of bolt cutters from her satchel and set them at an angle on the flimsy padlock bar, squeezing only slightly before the lock came apart with a metallic pinging sound, and she opened the box.

Underneath a sheaf of legal paperwork, at the bottom of the box, her hand closed around a black device, which on closer inspection turned out to be the receiver part of a high-end tracking device of the kind used by undercover operations.

Placing the device on the bed, she returned her attention to the box. There was a phone in there, the same make and model that Ruby had owned before the number changed. Was it Ruby’s? Too risky to leave it here, just in case. She pocketed the phone at the same time as she noticed: the metal box was much deeper, by two or more inches, from the outside than from the inside. There was a secret compartment.

“Jo? Have you found anything?” Atkinson’s voice floated through from the living space.

She felt in the bottom of the metal box, found a small ring attached to a chain and pulled. The false bottom came away.