Emperor Wen orders his fifth and youngest son, Yang Liang (assisted by the co-prime minister Gao Jiong), and Admiral Zhou Luohou, to conquer Goguryeo with an army and navy totaling three hundred thousand.

Yang Liang's army faces the early rainy season when it reaches Goguryeo in August.

The unseasonably heavy rain make the army's progress almost impossible and hampers the transport of provisions.

Constant attacks by Goguryeo forces and illness inflict heavy casualties.

Coming to the conclusion that the army cannot achieve the objective on its own, Yang decides to combine with Zhou's naval fleet and proceed.

Zhou's navy also encounters their own challenges, contending with rough seas, losing many ships despite staying close to the coastline.

Whenever they anchor, Goguryeo detachments are present to attack the Sui sailors.

The fleet engages in a battle against a Goguryeo fleet totaling fifty thousand led by Admiral Gang Isik, presumably on the present Bohai Sea.

Already weakened by ambushes and nature's onslaught, the Sui fleet suffers a devastating loss and Yang Liang is forced to retreat.