|Finishing this battle will set you on the Hypothetical route for Wu's story. In order to do this stage, you need to have acquired all stars on the battles prior on the stage select screen. Once you have done that, speak with Zhou Yu in the camp.|
At the beginning of the battle, head east and drop down nearby the bridge. Head north to the eastern base and you'll find Zhang Liao waiting, so take him down. Continue north and drop down into the central area of the battlefield, making your way towards Hefei Castle. Once inside, you'll notice the drawbridge is raised, so Wu decides to take another route to inside the castle.
It is about this time that Zhang Liao will reappear near Taishi Ci, but Lu Su mentions not to worry about it and continue towards Hefei Castle. Head to the western side of the map and climb the ladder to reach the cliff above. Inside the base there is Li Dian, so defeat him and then continue north.
Keep pressing forward, clearing the next base and then reaching the outskirts of Hefei Castle. In order to breach the gates, you're going to need some rams, but you need to lower the drawbridge first. To lower the bridge, you need to defeat Zhang Hu, but there will be a lot of other officers in the area, including Cao Ren and Zhang He who show up as reinforcements.
Once the drawbridge has been lowered, the ram will move to the gate, but before it will likely destroy the gate, Yue Jin and Li Dian show up next to the main gate. Defeat both of them and once the gates have been opened, all that's left is to take down Zhang Liao to finish the battle.