Imaginaerum informs the narrative of an older composer, Tom, that suffers from dementia. As he it has turned in to childhood and has the disease for years, he remembers nothing in his life. His music, friends containing the memory of his kid are a blur inside his delicate mind. All he has left is the imagination of a ten year old boy. It seems hopeless to get back what he gets lost, as he drifts off into coma. Or will it be?