Steam Ages - Day 5 is the fifth level of Steam Ages in the Chinese version of Plants vs. Zombies 2. It is a Special Delivery level. When this level is finished for the first time, the player gets coins..
In Normal mode, the player has to beat the zombies at Level 1.
The plants you get in this level are pretty powerful, so use them to your advantage. Be careful though, as Gentleman Zombies will prove to be an issue.
In hard mode, the player has to defeat leveled-up zombies.
Since you are forced to upgrade plants you likely do not own yet, this level is going to be extremely difficult. It is recommended to have level 4 Passionflowers because they appear frequently. Upgrading Electric Peashooters is unnecessary, due to the difficulty of doing so and the fact they do not appear as frequently.