Yuki and Sam's relationship splinters when Sam starts taking a new drug that could extend his life by a couple of hundred years. Yuki believes that the drug is a threat to society/humanity and that it's a privilege only available to the elite. Sam just wants more time because his creative ambitions have floundered.

This is a fascinating concept. Life quickly becomes bizarre, but convincingly so. People on the drug have to agree not to have children. They become risk averse because accidents are the only thing that'll affect their lifespan. Anxious to the extent that they pay extra in restaurants to have their food chopped up to reduce choking risk, they won't drive and they wear helmets to walk down the street. And the ones using the drug are almost all rich white people.

This is a cleverly written and layered novel set in England, Japan and America that feels almost prophetic. It's also a well realised reflection on ageing and mortality.
It's also a poignant relationship story. What happens if a couple still loves each other and one ages but the other one doesn't?

You'll love this if.you like beautifully written, near future dystopia. A captivating read.