Ellen is travelling home on a train. She's just had a thoughtlessly cruel message from her ex-husband's new partner, so happy about their baby's 12 week scan which has left her feeling raw and desperately saddened as she and he could not have a child together. A young mother sits in one of the few spare seats in the carriage, facing Ellen. When the young woman's phone rings, she asks Ellen to please watch her baby girl, Mia, while she answers the call. Before she comes back, the train pulls into a station and as it pulls away again, Ellen sees the young woman on the platform walking away. She mouths the word "sorry" to Ellen... Who is the strange man across the aisle who may have been taking pictures of Ellen and baby Mia and who seems to be trailing her as she walks through the station at the end of the line?