Forbidden Love in the Deep Palace

To save her mother, the female knight Yi Hongfu attempts to assassinate the First Prince, Duan Mo, but is instead blackmailed. Duan Mo exploits her striking resemblance to the late female official Lin Yuexi and sends her to the side of the Second Prince, Duan Zhen, using her as a femme fatale to sow discord between the brothers in their struggle for the throne.

CubeTV released it as 69 bite-size episodes mixing revenge and romance, made to watch on a phone in one sitting or a few.

If you came for revenge, the payoff is the slow build to a payback that lands hard. On top of that: the push and pull between two leads who shouldn't work but do.

At roughly 1–3 hours in total, it's quicker to finish than most full-length series.

Start from episode 1 below; autoplay takes you to the next episode when one ends, and nothing needs a sign-up.