Beyond The Shroud of the Universe. Codex Regius, #2

A mysterious race from an alternate universe has allied itself with the Jotunn, and the alliance is set on destroying the Aesir and bringing about Ragnarok. With an ability to jump between universes and unstoppable time-based weapons, the Efreet seem invincible. The Vella Gulf is the only ship to survive its first meeting with the Efreet.but only through a fluke of luck. Worse, Lieutenant Commander Shawn 'Calvin' Hobbs has just found out the Efreeti home world is the same planet in their universe as Terra is in ours.
If true, the Efreet could cross into our universe at any moment and annihilate the Earth without any warning. Terra lies defenseless!Calvin and the crew of the Vella Gulf have a surprise for the Efreet, though; they have returned to Terra with the ability to cross between the universes like their enemy. Armed with personal transporters and jump modules for their ships, they're now able to take the fight to the Efreet.
But will they be in time to prevent Terra's annihilation?As the Efreet continue their inexorable onslaught on all fronts, Calvin only knows one thing. The answers to all of their questions lie beyond the shroud of the universe.