Where is the mysterious checkpoint of the zombie hunting ground?

The mysterious checkpoint is in the cherry blossom city. In the first scene, the first place to attack was the entrance of the couplet. You need props and mysterious keys to open the mysterious level. After entering, fight Nian beast. Nian beast has no attack power, so it won't lose blood when attacked, but it will be dizzy. A * * * four-wave monster, a group of cubs plus an old beast is a wave of monsters. After each wave of monsters, a common treasure chest is given to the city of Sakura.