Time Travel, L Book #1 Fantasy, Steam Punk Singed 

The Lost Imperials  

Welcome to the war. The Tesla Institute is a premier academy that trains young time travelers called Rifters. Created by Nicola Tesla, the Institute seeks special individuals who can help preserve the time stream against those who try to alter it. The Hollows is a rogue band of Rifters who tear through time with little care for the consequences. Armed with their own group of lost teens--their only desire to find Tesla and put an end to his corruption of the time stream. Torn between them are Lex and Ember, two Rifters with no memories of their life before joining the time war. When Lex's girlfriend dies during a mission, the only way he can save her is to retrieve the Dox, a piece of tech which allows Rifters to re-enter their own timeline without collapsing the time stream. But the Dox is hidden deep within the Telsa Institute, which means Lex must go into the enemy camp. It's there he meets Ember, and the past that was stolen from them both comes flooding back. Now armed with the truth of who they are, Lex and Ember must work together to save the future before the battle for time destroys them both again. - from Amzon