I Can’t Keep My Sanity Anymore!

My name is Aaron, from an ordinary loving family. I was an honor student in all my school years and I was getting ready to enroll in a college. But one day I had a car accident while saving my little sister. This was the first time in my life that I have done something so daring, Unfortunately, it was my last time as well; as this moment of bravery cost me dearly, it cost me my life. Due to some absurd reason, my lifecycle has been halted for years and I wasn't reborn back on the Earth. Finally, I could strike a deal with the being who was holding on to my soul for so long; I have been reincarnated into the body of Ash, a rich heir boy, and was tasked with one mission, which was to change his fate! Later I found out that this boy had a girlfriend, how am I going to deal with her? Me who has never held hands with any girl other than my mother and little sister! Wait! That isn't all? My sister goes to the same school as that boy and now she is all grown up how much sticky this situation worsen? Read to find out...