A Modern Mind in Medieval Times

Hi. My name is Jack. This is the story of how I died and got a second chance to right the wrongs I had committed. A cocky go-getter nerd (think Mark Watney from The Martian) gets a second chance at life as a young nobleman, who *almost* died helping a persecuted people, and faces an uncertain future. Meanwhile, a Princess searches for a way to protect her realm from the looming threat of an expansionist power.   Jack is not your typical overly humble protagonist with an imposter syndrome, but he still has his own set of personal issues. He might not cower in the face of challenges, but is he ready for his new world? Will he be able to secure his people's future in a world where gods are real, there is no rule of law, no medicine and no toilet paper? What to expect:   -  A modern mind in the past done right.   -  A sensible protagonist. Jack might be strong, but he will always try to outwit his opponents before resorting to violence.    - Realistic characters that try to do good but might be tempted to do terrible things under stress.    - An interesting complete story. Plenty of twists and turns. The skeleton is finished, with only fleshing out left.    - Some romance, but it will not be the focus of the story.