When the kids discover that Mr. Benedict and Number Two have been kidnapped, they must piece together the riddles and clues within a perilous scavenger hunt set by Mr. Benedict to foil Curtain’s latest scheme.

Stowaways aboard a majestic ship, the kids try to blend in and find the next clue. Rhonda, Milligan, and Ms. Perumal board a dirigible to catch up to them. Mr. Benedict and Number Two do not hide their distrust from Curtain, despite his attempts to calm them. After observing the unnervingly joyful behavior of his devotees, they figure out that Curtain is using neurological techniques to create artificial happiness. Back at sea, the water polo team sneaks suspiciously towards the kids’ stateroom…

Heading to the train station, the kids realize that Curtain must have sent multiple teams after them. Benedict, in his state of involuntary elation, praises Curtain for his discovery.

The kids call in the help of an old friend as they scour the countryside for clues to Constance’s whereabouts. Meanwhile, Constance finds herself imprisoned by a surprising foe who hopes to shed light on an old failure.

After learning the location of Dr. Curtain’s compound, the Society prepares to strike but is beset by Greys and must split up to escape. Meanwhile, Mr. Benedict tries to bond with his twin in an effort to gain intel, but is sidelined as Dr. Curtain sows discord between Mr. Benedict and Number Two.

Mr. Benedict and Number Two’s plan to subdue Dr. Curtain backfires. After arriving at the compound, The Society regroups to rescue their captured comrades. Meanwhile, Dr. Curtain hosts a celebration to announce his plans for global expansion.

Freshly arrived at a haven from Number Two's past, The Society bands together to stave off disaster.