Knock Knock is an excellent continuation of the From Nothing series. The two older brothers get their HEA. Xavi and Nate were made for each other. There is a lot of banter, humor, and general tomfoolery -- just as in the first two books. It was also great to catch up with Maddox and Devin (despite what some reviewers suggest, I thought they were very much in character and provided great support for their brothers).