He noticed Siân’s blue Fiat Uno parked in a residents’ space just beyond the doorstep to her apartment building. She can’t have gone far, he thought, remembering the emotional state she was in yesterday morning, and feeling some relief. He pushed the buzzer, but there was no response; he stepped back and looked up at the building again. That was her light, without doubt; so he returned up the steps and pushed the bell again. Nothing. He checked his watch: he was only a few minutes late. Was she in the bath? He dialed her number again from his cell phone; the line was now busy. He pondered for a minute or two. She could easily reach the entry phone to let him in if she was talking—unless she was locked in conversation with Calvin and refusing to be distracted. Then he suddenly worried about whether she might have done something silly, and quickly pushed another bell. A voice on the intercom asked his name.

“Hi there. It’s Dr. Alex Stafford. I’ve come to see Siân, in flat five. The lights are on but she’s not responding to her bell. Could you possibly let me in? She should be expecting me, and I’m worried she might not be feeling well.”

“Which flat did you say?” the voice tested.

“Siân Powell—in flat five. I’m Will Stafford’s brother.”

“Oh yes—the doctor. The top-floor flat, isn’t it?”

Alex shifted his weight, suddenly impatient, and listened for the door release. As he pushed, he saw the long, badly lit corridor leading up the steep stairs that vanished into night. He moved quickly toward them. On the landing above the third floor, he paused for a hurried breath and realized he was tired. He’d left Grace rather late and hadn’t slept one complete hour afterward, hoping Lucy would call—fruitlessly, as it turned out—and an emergency had brought him in at six, meaning he’d just finished a twelve-hour day. Now he looked up toward Siân’s front door, and from this angle it seemed to be ajar. Odd, he thought; and he continued upward, before his eyes confirmed in poor light that the door was indeed unlocked. It was possible she’d gone up to the roof garden with a drink and left it open for him. He climbed the last two flights to the top of the building and pushed the hall light, which failed to come on. Trust Will to pick a place at the top of the world, with no elevator.