Elisabeth (Brenda Blethyn) is an English widow living on a small farm. She regularly visits the grave of her husband who died in the Faulklands War. She also attends a local church where the minister preaches that we must all learn to love our enemies. Meanwhile, in a Provencal field, Ousmane (Sotigui Kouyate), a gaunt African with dread locks, is praying toward Mecca.

Both of them are taken away from their ordinary lives by the July 20, 2005, terrorist bombings in London which kill 50 people and injure many others. Worried about her daughter Jane who lives in the city, Elisabeth calls her repeatedly on her cellphone but there is no answer. Growing more frightened by the moment that she may be one of the victims, this concerned mother takes a ferry to London. Jane lives in a slum, and Elisabeth is shocked when she discovers that her landlord is a Muslim.

Meanwhile, Ousmane has been sent by his estranged wife to find their son Ali. He left when the boy was only 6 years old and they haven't seen each other since then. A local imam (Sami Bouajila) volunteers to help Ousmane find his son. He gives the African a picture of Ali seated next to Jane. It turns out that they were living together, and she was taking a class to learn Arabic.

Elisabeth has led an isolated life and has some very rigid and distorted ideas about Muslims. She is appalled to learn that her daughter may have been thinking of converting to Islam. She is very uncomfortable around Ousmane. But despite these feelings, they are thrown together on a quest to find their children as they meet with the police, talk with a teacher of Arabic, and check in with the hospitals.

Writer and director Rachid Bouchareb has fashioned an engaging morality tale about the strange fruits that can grow out of terrorist attacks. In this case, a sheltered Christian who is fearful of the unknown and quick to pull away from strangers discovers that she and this Muslim have quite a lot in common despite their many differences. He is a very patient and quiet man who at just the right moment sings a song to her straight from his heart. By the end of London River it's clear that Elisabeth would understand these spiritual words from Henri J. M. Nouwen:

"Only when we have the courage to cross the road and look in one another's eyes can we see there that we are children of the same God and members of the same human family."