She pushed the door open slowly, and checked inside. A red tiled floor, white walls, old shelves, a boiler, washing machine and dryer were all still and silent. She stepped inside the utility room and shut the door behind her. An archway to her left led to a larder, shelves almost empty. She walked through a doorway into a large farmhouse kitchen.

An Aga squatted opposite, and pine units covered most of the walls. A large oak table and two long benches stood in the heart of the space, and a set of copper pans dangled from cast-iron hooks above a wood-topped butcher’s block that was off to her right. Photographs of the Asha family lined a dresser to Harri’s left.

This might have once been a warm, vibrant family kitchen, but it was now a mess. Used plates and pans filled the large butler’s sink, books, files and papers covered the table and benches, and the remains of meals on plates were half concealed beneath scattered documents. This didn’t look like a healthy environment for a child, and the mess made Harri reflect on the state of her own home. It was the sign of a damaged mind and she told herself she would do something about her own situation the moment she got back to her flat.

Harri removed a PCE-RAM radiation detector from a bag slung over her shoulder. The device looked like a simple mobile phone, with a small keypad and a large black-and-white screen. There was a circular sensor at the top that was designed to detect decaying particles. At least that’s how Dr Abiola had explained it when she’d demonstrated how to use the device. Harri switched it on and examined the display to see the readings within normal range. Dr Abiola had told her what to look for: a sudden spike in levels would indicate the presence of an isotope. If she found the Cobalt 60, she was to phone an emergency number and the relevant authorities would be notified and a clean-up team dispatched to recover the radioactive material. Under no circumstances was she to touch it.

Harri ran the detector over the papers scattered on the table and saw nothing abnormal. The documents seemed to be a mess of mathematical formulae, and there was a line or two of strange poetry here and there. The formulae made no sense to Harri, and neither did the out-of-context poetry. She swept the rest of the room before moving into the hallway.

The detector registered normal as she walked on. She opened the cloakroom door and leaned in, reaching into her pocket for her phone. She’d get a picture of the Elsewhere House poem this time, but her plan was thwarted. The poem was gone and had been replaced with a photograph of the Elsewhere House itself. Unsettled, Harri backed out. Had he put the poem there for her visit? Or was the photograph another message? Why would Ben have a picture of Elsewhere in his house?