This is the third book in the series. If you remember, and if you don't boy won't the next few sentences come in handy, gates to other planets started opening all over the Earth. Some gates opened to peaceful places while others opened to desolate place. Still other gates proved more problematic as aliens, intent, evidently on conquest, began pouring through them.

In response, the United States puts together a team to come up with solutions and one of those solutions is a submarine that is made space worthy. This is the second book revolving around the voyage of that sub. In this case, right after having come home from the first voyage the sub needs to go back out in response to the cutting off of communications from a deep space colony. The crew is pulled back together and the sub is launched and soon on it's way to further adventures in the unknown. Along the way they make friends, find more enemies and use ingenuity to solve all sorts of problems.

Ringo and Taylor combine to produce a tale that is fringed with humor while dealing with a serious subject. The characters are lighter than one finds in Ringo's works along and more energetic than in Taylor's solo efforts. this synthesis produces a read that is both fast paced, enjoyable and lacking in the haughty tone that so often accompanies this branch of military SF. The big difference here is that the characters are capable of making fun of themselves.

I've found the series, so far, enjoyable and entertaining and worthy of picking up. The science seems genuine, the military action based in fact and the premise, while unusual, hard to argue against. I've enjoyed all the books in the series and am looking forward to the next one.