Mary Hussain (Joanna Scanlan) converted to Islam when she married her husband Ahmed, and has a close and loving relationship with both her husband and his family. When Ahmed dies suddenly and unexpectedly, Mary finds herself a widow in her early 60s. A day after burying her husband, she discovers that Ahmed had a secret life just 21 miles away from their Dover home, across the Channel in Calais.

This shocking discovery compels Mary to travel to Calais to find out more. As she grapples with her shattered sense of identity, her search for understanding has surprising consequences.