Unspoken (The Vampire Diaries, #12) by L.J. Smith

Death is only the beginning.…

Elena Gilbert’s entire world has shattered in a single moment. Her true love Stefan is dead, staked through the heart by their so-called friend Jack. Now the only thing Elena cares about is destroying Jack and his race of scientifically created vampires.

But Jack’s creations are impossible to kill—immune to sunlight, stakes, and every traditional weapon against vampires. Elena and Damon set out to uncover the mystery of Jack’s dark past in hopes of finding his weakness. As they spend more time together, Elena and Damon can’t deny that their connection is stronger than ever. Can she face her feelings for him without betraying Stefan’s memory, or are some things better left unspoken?