by Steven Gould
Reflex is the sequel to Jumper; these books will be more enjoyable and be easier to follow if read in chronological order. However, this story takes place ten years later on, and while it does continue a major plot arc, you're not jumping into the middle of an ongoing adventure if you start here.
This story follows Davy and his wife Millie -- but mostly not together. The story starts with Davy being kidnapped, which accidently strands Millie in a safe-house that is inaccessible to anyone who cannot teleport. She cannot teleport. In trying to escape she almost dies, but saves herself by spontaneously and unexpectedly teleporting. This opens up a lot of new possibilities, and new troubles. A large portion of the book follows Millie's investigation of Davy's abduction, with the help of her newfound ability.
The rest of the book is about Davy being tortured and experimented on. A mysterious and very powerful organization really wants to know how teleportation works, and is more than willing to do some invasive medical research on the only person who can do it. Davy is hardly passive during this process, and he has some tricks up his sleeve. So do the bad guys. It's a pretty dark story.
As with Jumper, this is a fast moving and exciting adventure. It fits well with the first novel, being a bit dark, having clever solutions to new problems, and doubling down on making teleportation an interesting power. If you liked Jumper, you should obviously read this as well. The next book is the series is Impulse, although there is also a short story, Shade, that fits between them.