Damn It, the Sour-Faced Shadow Guard Is Actually a Softie at Heart

[Dual male leads + General x leader of the secret guards + transmigration + System + a little angst + sweet romance + both inexperienced]

The general is charming and considerate, and dependable when trouble arises.

The leader of the secret guards looks sour-faced, but is actually soft-hearted.

He transmigrates into the body of a young general of the Yan Dynasty, famed for his outstanding military service. But the general is framed by villains as a traitor in league with the enemy and dies a tragic death at just twenty-five.

The System assigns him a mission: change the general's fate of being framed, overturn the historical record of the Yan Dynasty's downfall, and uncover the real traitor whose name was never recorded in the history books.

The leader of the secret guards is ordered by the emperor to investigate the general's alleged treason.

The general and the leader of the secret guards can't stand each other.

Meanwhile, a modern-day office drone from the twenty-first century, wearing the general's face, pretends to be crazy and foolish in hopes of getting away with it.

The System takes a back seat later on.

This is an alternate history, so don't take it too seriously.

Just read for enjoyment, and don't overthink it.