What a Nightmare: Trapped in the Tang Dynasty with a Female-Led Novel's Protagonist

As the Tang dynasty’s Marquis of Zhenyuan, I’m the youngest meritorious marquis in history! A transmigrator! Tang Chen, a big shot in the military, thought his life was set. He had every advantage imaginable. So why did he discover a new transmigrator as soon as he returned to Chang’an? And she’s the heroine of a romance novel, no less!!! We’re doomed!