My Concubine Can't Possibly Be the Crown Prince!

[Main story complete, bonus chapters coming soon] [Sunny, energetic, badass bottom × sickly, possessive, gloomy top] Jiang Mian, an employee of the transmigration-into-a-book bureau who was about to retire, landed in the story six months too early. So, naturally... he decided to enjoy his retirement ahead of schedule on the company dime. Hahaha! Over the next six months, Jiang Mian not only got himself healthy and well-fed, but also met the love of his life. The beauty had a lovely face and a good temper, and was perfect in every way. The only problem was that he was terribly frail, bedridden with illness every few days. He even claimed he was doomed to die young and had no blessings to look forward to, and would only agree to be Jiang Mian's kept man. Marriage was out of the question. Whether he was blessed or not was one thing, but doomed to die young... Jiang Mian looked at the nearly empty health bar over the beauty's head, and his heart sank. Luckily, he had a cheat. The catch was that using it on a partner required enough intimacy. Well, being a kept man wasn't out of the question. First, they just had to hold hands, kiss... Ahem, build up enough intimacy to cure his illness! Right, the most important thing was to cure him! * The plot kicks off: it's the familiar struggle among the emperor's many sons for the throne, but while the premise is basic, the mission difficulty certainly isn't. Jiang Mian gets a legendary-level mission: a worldline riddled with bugs. He has no idea what the bugs are, the system backend works only sporadically, and people resign in disgrace all the time. Jiang Mian: ... Jiang Mian: Fine. The mission proceeds in a state of constant anxiety, full of bumps and setbacks, always on the verge of falling apart. After a while, Jiang Mian makes an unexpected discovery: whenever the beauty is with him, the plot unfolds unusually smoothly... He knew he was a lucky star! After finally holding out until the emperor's death, at the point when all the princes are supposed to take one another down, Jiang Mian prepares to usher the male lead onto the throne. He marches into the palace at the head of a large army, making a grand entrance. But amid the flames, the crown prince, who should have died long ago, is firmly in control of the palace with a mighty army at his side. And he looks strangely familiar, almost like... the kept man he treasures above all else? Jiang Mian: ? The crown prince's face turns livid as he reaches out to Jiang Mian from across the distance. “Come here.” Jiang Mian: ?? That's weird. His voice sounds familiar, too. * Yan Zhixing was born the crown prince of Great Yan, a man of supreme status. Sadly, he was born frail, and all the imperial physicians said he would not live past twenty. His father and maternal relatives searched everywhere for renowned doctors, but Yan Zhixing knew there was no point... Ever since he was a child, he had been able to see things no one else could. Everyone had a red line and strange characters above their heads. Only when he grew older did he learn that the red line was a lifeline, and that it could change. His own lifeline had been short since childhood, and nothing had ever made it budge. Just as his lifeline was nearly depleted, he met someone whose head was completely clear, with nothing above it. After they lived together for a while, Yan Zhixing saw his own lifeline for the first time. Slowly, but unmistakably, it grew a little longer. Theme: No flight is free from the pull of gravity.