Here is the description from Amazon:
Humankind may have won the battle, but a new threat looms larger than ever before....
Earth's armed forces have stopped the Lanky advance and chased their ships out of the solar system, but for CDC officer Andrew Grayson, the war feels anything but won. On Mars, the grinding duty of flushing out the twenty-meter-tall alien invaders from their burrows underground is wearing down troops and equipment at an alarming rate. And for the remaining extrasolar colonies, the threat of a Lanky attack is ever present.
Earth's game changer? New advanced ships and weapons, designed to hunt and kill Lankies and place humanity's militaries on equal footing with their formidable foes. Andrew and his wife, Halley, both now burdened with command responsibilities and in charge of more lives than just their own, are once again in humanity's vanguard as they prepare for this new phase in the war. But the Lankies have their own agenda...and in war, the enemy doesn't usually wait until you are prepared. As Andrew is once again plunged into the chaos and violence of war with an unyielding species, he is forced to confront the toll this endless conflict is taking on them all, and the high price of survival...at any cost.