X Middle School's bathroom renovation project teeters on the brink of disaster as the new tagger "STAINLESS" strikes at will. Out of leads, Fillmore and Ingrid turn to Randall Julian, the former vandal "FLAVA SAVA," currently in solitary detention. His help puts them back on the trail, but Randall escapes, forcing Fillmore and Ingrid to hunt down both "STAINLESS" and "FLAVA SAVA" before they strike again...

The student body is in an uproar when the controversial S.A.T.T.Y. 9 tests are stolen by an assailant dressed as X's beloved mascot, Lobstee the Lobster. Who is the thief - a student who panicked during the test? Or was it Enid Quintara, outspoken anti-S.A.T.T.Y 9 activist? Fillmore and Ingrid are under the gun - they have only 48 hours to find the tests or Principal Folsom will force the entire school to take the tests again.

The Library's books have disappeared, and Tony Clementina, X Middle School's local heavy, is all too eager to take credit for it. Meanwhile, an empty can of Carbee Cola leads Ingrid back to the biggest custard spill in X Middle School history, an incident that disturbingly points to Fillmore. Cases closed - or are they?

Someone has stolen X Middle School's beloved mascot Lobstee the Lobster. Time is running out for both Lobstee and the Bocce Team, and the key to finding him before time runs out might be X's resident psychic, Alistair Greystone. Will Alistair and the Safety Patrol find Lobstee before it's too late, or is the psychic a fake?

During an undercover sting operation, boxes of Band candy were accidentally discovered in the lake. The candy is traced back to the Red Robins - seemingly a school club in the same manner as Girl Scouts who make record sales of their award-winning taffy. In reality, the Robins strong arm their competition (stealing candy and cookie dough, cheating in selling taffy, messing up signs of competitors), and the Safety Patrol have been trying to catch them in the act for a long time. Ingrid goes undercover as a Red Robin, but she fits the role all too well and becomes the shoe-in for becoming the leader of the Robins when Malika, the current leader, graduates. Fillmore discovers that Malika used to be Vallejo's partner who also infiltrated the Robins, but was seduced and overcome by the dark side. Will Ingrid find the secret Vault of stolen goods and shut down the Robins for good, or will Ingrid also turn to the dark side as Malika did?

Who sabotaged the Model Train Convention? The R/C Car Club, or was it an inside job?

Duappy, a virtual pet - the virtual pet kept alive the longest - has been stolen, and it is up to Fillmore and Ingrid to find X's pride and joy before a reporter comes to X to do a story on Duappy and before Duappy dies. But what if Duappy was stolen not to harm, but to help...

Fillmore's partner moves away to Tennessee, and he is partnered up with Brad Parnassus, the smartest kid at X Middle School. Rebellious and super-smart new student Ingrid Third doesn't take her introduction to X student body well at all, and a giant stink bomb explodes in the hallways. The case looks like a slam dunk - or is it?

Mrs. Cornwall's Pre-Algebra final exam looks like it's going to be a tough one; however, four of her students have decided to take more extreme measures beyond studying. Fillmore sleeps over in the school to safeguard the exam, but an unexpected blizzard leaves him standing alone to face a desperate gang of determined exam thieves.

Mrs. Lawson's field trip to the Modern Contemporary Natural History, Art, Science and Miniature Museum takes a horrifying turn as someone draws a mustache on the priceless painting "The Lobster Man at Port". Fillmore, Ingrid, and O'Farrell work to find the culprit and save the painting, but the clock is ticking and everyone's a suspect...

Scooter thefts are up, and the Safety Patrol faces a challenge from student activist Derek Minna, who establishes B.A.G.A.S.T. (Boys And Girls Against Scooter Theft), a scooter and rollerblade equipped task force that he intends to ultimately replace the safety patrol. Fillmore and Ingrid trace the thefts to the Metal Shop and infiltrate the gang. Who is the mysterious "Stingray," and what are his plans for the stolen scooters?

X Middle School's best hope to break a losing streak is Checkmatey, a flamboyant rapper who is X's finest chess player. Unfortunately, somebody is out to get him - is it Tyson Pelarez, leader of the Society of the Preservation of Ethics in Chess? Or is it Nelson Kelloch, Checkmatey's biggest rival? (Checkmatey also has a crush on Ingrid, which repulses her). Fillmore and Ingrid are on the case - but the clock is ticking down to the championship match and Checkmatey is nowhere to be found...

The heat is on from Student Council Representative Peabody to get illegal term papers off the street, but the perps always seem one step ahead of the Safety Patrol. After a botched raid and the sabotage of his bike, Fillmore turns to Sonny Lombard, his old partner from his bad-boy days. They track the papers back to Rudy Teravall, the Kingpin of Home Economics, but just as Fillmore and Ingrid get ready to move in on Rudy's gang, Peabody gets tipped off about bootleg hall passes in Fillmore's desk. Fillmore gets suspended from the force - but has he really gone bad again? And just what is Sonny's real agenda?