The Emperor's Son-in-Law in the Zhenguan Era

Yu Tian died of a sudden attack of congenital heart disease on his way home from work. The rescue attempt failed, and amid his family's immeasurable grief, his soul transmigrated to the second year of the Zhenguan era of the Tang Dynasty. Make money? Of course. What was he supposed to do without any? Marry a princess? Sure. He never imagined a loser from the future could marry a princess. Fight in a war? He couldn't do that, but he had a transmigration starter pack! Just wait, he'll whip up something good for you...