Harriet works as a management consultant in London. At the request of her childhood friend Tim, she's been pretending to be his girlfriend for the past three months. Then she runs into his older brother, James, a successful architect with devilishly handsome looks, who also happens to be her first love. One day, he comes to check on her in her time of need, and as one thing leads to another, old flames burn bright once again. But how can she tend the flames with James and still keep secret the hidden truth behind her promise to Tim?