1. Disappearance: In the first book, "The Bad Beginning," the Quagmire triplets - Quigley, Duncan, and Isadora - are mentioned as orphans living at Prufrock Preparatory School, the same boarding school where the Baudelaire children attend. However, shortly after the events of the book, the Quagmires mysteriously disappear without a trace.
2. The Quagmire Files: In the subsequent books, it is revealed that the Quagmires were kidnapped by Count Olaf, the villainous antagonist of the series. In "The Vile Village," the Baudelaires encounter a secret organization known as the "V.F.D. (Volunteer Fire Department)" that has been investigating the disappearance of the Quagmires. They discover that the Quagmires were taken because of their valuable knowledge and the mysterious device known as the "Sugar Bowl" in their possession.
3. Rescue and Separation: In "The Carnivorous Carnival," the Baudelaires are briefly reunited with Quigley Quagmire, who has escaped Count Olaf's clutches. It is revealed that Quigley was held captive in a traveling carnival. Unfortunately, the reunion is short-lived as they become separated again.
4. Mysterious Clues and Appearances: Throughout the series, the Baudelaire children continue to encounter clues about the Quagmires' whereabouts and the secret organization V.F.D. They meet Isadora Quagmire, disguised as a fortune-teller, in "The Ersatz Elevator." Meanwhile, Duncan Quagmire remains missing and his fate is shrouded in mystery.
5. The Ultimate Fate: In the penultimate book, "The Penultimate Peril," it is revealed that Duncan Quagmire has indeed passed away. The circumstances of his death are tragic and involve the V.F.D. headquarters. Isadora Quagmire emerges as a resilient survivor, but the fate of the Quagmires remains bittersweet as they endure the chain of unfortunate events that befalls them.
6. Final Reunion: In the final book, "The End," the Baudelaire children and Isadora Quagmire are finally reunited on a distant island. They form a new family and find solace in each other's company. The Quagmire triplets' journey throughout the series, though marked by tragedy and separation, emphasizes the importance of resilience and hope in the face of adversity.