Star Trek: Renegades (2015) online

It is nearly ten years after Voyager's return from the Delta Quadrant, and the Federation is in a crisis. The Federation's main suppliers of dilithium crystals are disappearing. Space and time have folded around several planets, effectively isolating them from any contact with outside worlds. And this phenomenon is not natural - someone or something is causing this to happen. This necessitates drastic measures; some of which are outside the Federation's normal jurisdiction.