Mallory gets a chance to meet her idol, ace forensics expert Alix Ang, but the casual meet-and-greet turns serious when Alix and Mallory, together with Mallory’s friends Nadia and Juraimi, make a discovery that leads to a most perplexing case.

A leftover clue from a previous case leads to a brand new mystery: the curious case of the cat with two owners! Mallory enlists a reluctant Alix to find the feline’s true owner, while Juraimi tries to get out of remedial and Nadia learns that there might be more than meets the eye about her friend Vik’s absence from school.

When the school’s Guitar Club target the Drama Club for revenge, Mallory and Alix become embroiled in a cold case that has gone unsolved for more than half a decade. Meanwhile, Mr. Yew Kang and Ms. Tasha’s squabbling leads to drama in the Drama Club.

Mallory’s attempts to impress Alix inadvertently leads them both to Auntie Pek, the neighbourhood cat lady, and her claims that someone is poisoning her feline friends! Nadia and Juraimi fight over who is truly Mallory’s BFF.

Mallory takes it upon herself to get to the bottom of things when her father Yew Kang’s car is vandalized, leading to conflict between her, Yew Kang and Alix. The “missing” Vik makes a sudden reappearance, but when the kids press him for answers, it turns out that he too has more questions than answers.

Nadia flips out when her study notes go missing just before a big test, leading her to accuse Juraimi of the theft – Mallory has to find out who is really responsible in order to save their friendship. But having just fallen out with Alix, does Mallory have what it takes to go solo?

Mallory has a crisis of confidence, and decides to retire as a detective. Her friends Nadia and Juraimi have a plan to restore her faith in her skills – and it involves an escape room! Meanwhile, Alix is hired by Vik to get to the bottom of his father’s recent suspicious behaviour.

The school’s soccer team is down with food poisoning before the big game, and Mallory is enlisted to find out if it’s a case of sabotage, as some suspects. Alix agrees to help chaperon a school trip with Yew Kang and Ms. Tasha, only to find that someone might be stalking Vik.

Still at loggerheads, Mallory and Alix are forced to team up to take down fake psychic and possible scam artist Rainbow Rosie. But when Rosie claims to be able to communicate with Mallory’s late mother, the duo’s faith in science and each other is shaken.

Mallory, Nadia and Juraimi fake a ghostly encounter to prank Yew Kang, Ms. Tasha and their friends while out on a camping trip – but find that a monster may really be on the loose! Alix digs deeper into the mystery of Vik’s stalker, and how his father may be involved, and uncovers something disturbing.

The school’s year-end exam papers have been stolen! When the infamous hacker MsCh13f claims credit, Mallory and Alix have to find out how he did it and prevent the next attack. Nadia helps Juraimi look for the class pet when it goes missing, but discovers something that would have devastating effects on Vik.

The lingering mystery behind Vik’s brief disappearance comes to a head as those responsible kidnap him, his father and Nadia in order to recover a priceless historical artefact. Mallory and Alix, with help from Yew Kang and Juraimi, work against the clock to rescue their friends.