Before the Coffee Gets Cold

This book takes place in Cafe Funiculi Funicula in Tokyo. It may look like a regular small cafe, other than the fact that it is in a basement, and has three clocks that don't show the same time, but it hides a bigger secret.  Following a set of rigid rules, visitors to the cafe may travel in time! The book follows the story of four different people looking to find closure, healing, forgiveness, and acceptance.
One of the main rules of time travel in Cafe Funiculi Funicula is that no matter what you do in the past, you cannot change the present. They also have to drink their coffee before it gets cold to return to their present, otherwise, they will face harsh repercussions. So what motivates people to travel back in time to their pasts? 
We meet a woman whose boyfriend left her to go to work in America, and she regretted not asking him to stay. We meet a man who has Alzheimer's, and his wife who is heartbroken because he cannot remember her anymore, and they attempt to define the parameters of their new dynamic. 
We also meet a woman who is estranged from her family, and who kept rejecting her sister's attempts to reconnect until she lost that sister. And, finally, we meet a pregnant woman who knows she is going to die if she carries on with her pregnancy, but all she wants is to give her baby a chance at life and make sure that they are happy. Each of those people was seeking closure, forgiveness, or an attempt to express their feelings one last time, and even though none of their presents changed, they all managed to find some peace.