Looking at Lanyu Party Case from Zhu Yuanzhang's Setting Up the Crown Prince

Zhu Bao is Zhu Yuanzhang's son given birth by his wife, who is set up as the crown prince after Zhu's office starts and trained to be the future emperor. Lanyu, who is the brother of the crown prince's brother, has already started a feud with Yan emperor who is seeking the throne due to his sparing no efforts to protect Zhu Bao's crown position. Yan emperor pretends to be honest and loyal gaining father emperor's appreciation and waits for chances to eradicate his enemies. At the meantime, father emperor and the crown prince are gradually divided in political opinions, and the crown prince dies prematurely because he is frustrated in political affairs and contracts disease due to the unhappiness and frustration. The crown grandson is too young to be the successor. For succeeding emperor's throne, the emperor Zhu makes the case of murdering Lanyu party under Yan emperor's instigation and the suspicion of himself.