Blake Crouch, Upgrade

Logan Ramsay lives with the guilt of having been involved in his brilliant mother's accidental destruction of the world as we know it. Now, with lower Manhattan under water and dark gene labs producing exotic new species to sell to Russian oligarchs, Logan is doing his penance as a federal officer tracking down rogue geneticists—at least until he's attacked at a cellular level and transforms into a kind of superman. And then he needs to save the world, more or less. Logan's metamorphosis is pretty far out there, of course, but it's so well described that it all seems very believable. There's a lot of science-y explanations throughout the book that lend the story credibility (but at the same time feel a little skippable). The dramatic battle at the end was a little hard to follow and felt rushed, but the story was capped off with a sweet epilogue that left me more contented than I would have been without it.