At the beginning of the series, the Secret Scientists are attacked en masse by V.V. Argost, the masked host of the cryptid-centric television series V.V. Argost's Weird World and a longtime enemy of the Secret Scientists. Argost and his henchmen steal the pieces of the Kur Stone, a Sumerian artifact which can lead its wielder to the location of Kur, an allegedly all-powerful cryptid. In the first season of the show, the Saturdays are also pitted against bounty hunter Leonidas Van Rook and his apprentice, who is later revealed to be Drew's long-lost brother Doyle Blackwell, who was separated from her after their parents died in an accident in the Himalayas. The Saturdays also discover an ancient mirror which leads to a dimension made of antimatter, and encounter their evil counterparts, whom Zak dubs the Mondays. At the end of the first season, the Saturdays and Argost race to Kur's supposed resting place in Antarctica, only to discover that Kur is actually Zak; when the Kur stone first shattered years ago, Kur's soul entered Zak's unborn body, which is the origin of Zak's cryptid-influencing powers.