It is no use, but William gives Isobel 90 minutes anyway. They were once married, but something happened. Something broke deep down in the mechanism of their lives together and, seeing no way to repair it, they threw it away.
But perhaps they were too hasty. Perhaps there was something they could have done. Isabel just wants 90 minutes. Soon William will be married again, so 90 is all she has to make her case. Ninety to remember what they had. Ninety to regain what was lost. Just 90 minutes to rediscover love or call it a day, forever.