Experiment gone wrong

The story revolves around a pair of siblings who are in the military, when the elder sister was picked to participate in the field test for a certain military project that may evolve the military force drastically. However, on her mission, the elder sister went missing along with the military gear she was given. The colonel in charge of the mission decided not to report the loss of the military gear and decided that the younger brother wold replace her in the mission...P.S: I am sorry that I had not planned the other novel properly and had to cancel it. As always, please give me feedback if you have any opinions or suggestions to help improve the story