While helping clear her grandmother's attic, Imani found a brass lantern wrapped in an old theatre programme. It had three sliding glass panels: clear, red and green. Scratched into the handle were the letters R.M. and the date 1948.

Grandma did not recognise it, but she remembered that the town theatre had once stood beside the railway. Imani carried the lantern to the local museum, where Mr Vale turned it carefully in his gloved hands. It was not a theatre prop. Railway workers had used lamps like this to send signals at night. Green meant a train could continue; red meant stop.

The initials led them to Rosa Malik, listed in a 1948 staff photograph as one of the station's first female signal operators. In the picture, Rosa stood on the platform holding the same lantern.

The museum already owned the photograph but had never known what happened to the lamp. Grandma donated it, and Imani wrote its label. She left one mystery unsolved: nobody knew how Rosa's railway lantern had come to be wrapped in a theatre programme in Grandma's attic.