Since the Notebook of Doom was stolen Alexander and the other monster hunters of Stermont Elementary have been operating without its assistance and now they are confronted by a large and stinky monster with eight powerful noses that can deliver a slimy sneeze with the power of a cannon--and somehow they must figure out its weakness.

Alexander keeps seeing monsters he has previously conquered, but every time he gets close they disappear and his friends are beginning to think he is delusional--but when one of their teachers turns into a blob of super-goop right before their eyes they realize the team is dealing with a shape-shifter, and it is after the Notebook of Doom.

It is time for the Stermont Derby, a race around downtown Stermont in homemade vehicles, and Alexander, Nikki, and Rip are planning to compete, but so is a new monster, a Speedah-cheetah--and in addition to a diet of rotten eggs it plans on eating the race losers, especially the members of the Super Secret Monster Patrol.

It has been several months since monsters last plagued the town of Stermont, and frankly Alexander Bopp (leader of the Super Secret Monster Patrol) is bored, and misses his friends Rip (immersed in video games) and Nikki (soccer camp), so when his father signs him up for a summer maker program at the library he is happy to go--but soon he starts finding weird old-timey objects, and monster trading cards, and it starts to look like maybe monsters are...

It is a very hot summer in Stermont, and Alexander and his friends are at Camp Gloamy in the mountains, but even here there are monsters--specifically zombie snowmen called snombies who want to freeze the young monster-hunters.

Alexander has just moved into Stermont, but the elementary school is being torn down, his new classroom is located in the hospital morgue, a notebook he finds is full of information about monsters--and everywhere he turns there are spooky balloon men determined to attack him.

Alexander and his new friend, Rip, are worried that the worms the rain has brought out are really the megaworms that Notebook of Doom describes but they soon discover that the night crawlers are trying to warn them about the monster tunnel fish that are threatening Stermont Elementary.

Something is stealing machine parts from all over Stermont, including a wrecking ball from a local construction site, and Alexander and his fellow monster hunters, Rip, and Nikki, fear that it is building a Stermont-smashing machine--so the friends must use the resources of the summer maker program at the library to stop this monster, and perhaps even solve the mystery of who is leaving monster trading cards where the Super Secret Monster Patrol can...