Just a word of warning. If you haven’t started this series, pick up Operation: End Game before you read this review. I don’t write reviews with spoilers but content in this review will contain spoilers for the first book in the series. ;)Readers were only given a glimpse of Colton in Operation: End Game. Just a taste of who he really was. The main focus was on Cassie and Jake, which is how it should have been. No complaints, because I really liked them as a couple. They were the perfect choice to start the series. I’m kind of glad that we didn’t get to know Colton any better in the first book. I think it made Operation: Endeavor a lot more interesting. Sure, Cassie and Jake are still my favorite couple, but I gained a lot of respect for both Colton and Penelope in the second installment of Christi Snow’s When the Mission Ends.Colton is more than your average big brother. His need to protect and his strong sense of responsibility for his younger siblings started when he was only 10. He never grew out of that role and given everything that all of them had been through the previous year, you couldn’t really blame him for being overly protective. It wasn’t just that though. Even though he was relieved to have his brother back, he wanted him whole. That forced him to push and the tension between all of them became almost unbearable. Long story short, big brother Colton was getting on everyone’s nerves. Perfect scenario for Colton to find a new place to live. The most unlikely person for him to end up with was Cassie’s college friend, Penelope. Who knew how perfect that pairing would be?There was a lot more to Penelope than met the eye. It shouldn’t have been a huge surprise that she wasn’t nearly as flighty as we were first led to believe, she was Cassie’s friend after all. We knew that she was a loyal friend. She proved that more than once in Operation: End Game. I can’t say a lot about what makes Penelope so much more because she was so full of surprises that readers deserve to discover them on their own. (Colton had fun figuring them out as well ;) )I’m not sure I can pick one thing about this series that I like over another. The dynamic between the siblings and their friends is great. The dialogue flows easily and the author’s writing style pulls you into the story line. Once again I started reading this one and was half way through before I knew it. I love it when that happens! That combined with the action, danger, heart break, surprises, twists and turns make these books really hard to put down. Oh yeah, and did I mention the romance? Operation: Endeavor wasn’t lacking in that department at all. Despite the fact that they both fought the inevitable, the connection between them was amazing and at times heart breaking. I have to say, the turning point for this couple was great. It wasn’t forced and the timing made perfect sense.Complaints? Not really. The only thing that bothered me at all was the way that first Cassie in Operation: End Game and then Penelope in Operation: Endeavor both make really stupid and careless moves that put them in danger. As a reader you know it’s going to happen. You want to reach into the book, grab them by the arm and force them to stop and think. The momentarily lapse in good judgement is a turning point, it’s a necessary element and I can almost forgive Penelope because she put someone else’s safety before her own, but it still drove me nuts.So what’s next for the Robertson siblings? Christi Snow has a treat for readers before Operation: Endurance is released in April of 2013. Operation: Before the Mission Begins is a novella that takes place before the first book in the series, but it is meant to be read between books 2 & 3. It will be available in February of 2013. Both books feature Chris. I’m waiting for both of these books with a tad bit of trepidation. Not because I’m afraid they won’t be good, I have no doubt that they will be as amazing as the others. Readers were given just enough of what’s possibly in store for Chris in Operation: Endurance that I’m pretty sure it’s going to be an emotional roller coaster for everyone involved.