N₂+3H₂→2NH₃ is the final stage in Summer Lesson.
- The stage begins with a St. Pigge the 2nd, followed by three Pigges.
- After 40 seconds, an Owlbrow spawns, with another one spawning 10~13.3 seconds later.
- After 100 seconds, Pigge starts spawning in 30~50-second intervals.
- When the enemy base is attacked, Doge Dark, Teacher A., Shadow Boxer K and Gory Junior emerge.
- Doge Dark continues to spawn in 6.7~13.3-second intervals, while Gory Junior spawns in 16.7~23.3-second intervals. In total, there are 17 Doge Darks and 6 Gory Juniors.
- After 20 seconds, another Teacher A. is spawned, and after 30 seconds, another Shadow Boxer K spawns.
Crazed Whale Cat, as it will chip the Teacher A's health quicker, anti-Black cats if you are having trouble with the Shadow Boxer K, Artist Cat/Ramen Cat, and Dragon Cat/Crazed Dragon Cat are all also good units to use, the Dragon Cats/Crazed Dragon Cats in particular are good for chip damage.
Battle: Upgrade your Worker Cat to level 3-4 while waiting for the Pigge to go near your base. Once it comes to your base, spam your meatshields while waiting for money. Once the Owlbrow comes, start spamming Paris Cat. By killing them, you will get the money to spawn Bahamut Cat.
Keep spamming meatshields and Paris Cat. Once you hit the base, the rush of enemy will appear, and hopefully your Bahamut Cat gets a shot and hits the Shadow Boxer K, as it is very dangerous. The peons will then give you money, which you can use to upgrade your wallet/send out Ubers. Once you have max money, turn on Cat CPU, or if you don't bring one, keep spamming Paris Cat and your meatshields. Your Paris Cat will chip away the health of Teacher A, and you will get 3 Lucky Tickets upon your first time victory.