In Break-In At Bleak End, Merc Firewater was still figuring things out; his training with Stratus was hitting some rough barriers, and he literally killed himself after throwing himself off a ledge, only to be brought back by wild magic. Agreeing to re-meet in a week, he returned to his stall near-dead. He didn't have much time before Nessa and Elle approached him: Merben Ordri Fizzlehide Pennyluck had gotten himself into trouble with the Glitterati. Realizing that his old boss needed help, Mercy agreed to help when Poons suddenly appeared in his stall, and all three went to the Pixis Palace before the guards chasing her found them.
Don Coriander Thorn requested that the former Crew steal a key from Bleak End, in exchange for Merben's life and a small percent of the take. During negotiation, Elle noticed sympathy from Snapdragon Poplarchop, and learned from him to contact Captain Jolly of the Jolly Dodger. At a cut rate, they boarded and sailed to Farrozandmar, seeking out the Plot and Hook. They learned from Hollyhock Barrowes that only Prisoner 13 knew of the key's location, and were given Bleak End Magical Maps that acted as arcane lockbreakers. To enter the prison, they decided to knock out incoming staff and pose as new employees, keeping their targets in the hull of the Dodger in the meantime - Merc posed as cook Mica Langelo, not realizing that the charlatan had been boasting he was a world-class chef.
The former Crew successfully entered Bleak End, learned how to moved around the prison without arousing suspicion while adopting work, and Mercy somehow made a good impression on his boss Tiny Tulvrak, lying that his hands were too broken to cook. The sorcerer had to use magic to pin the blame of an escape attempt on Prisoner 76, but save for that close call, they integrated flawlessly. Elle was able to pass as a fantastic chef on Merc's behalf, ingratiating them to staff and inmates and opening up social avenues. They managed a perfect plan, contacting Prisoner 13 with the intent to break her out. However, the dwarf wanted to remain in the prison, but was willing to trade the key's location for the Bleak End Records of Imprisonment.
With magic and guile, Poons and Nessa stole the ledgers in the surveillance tower, as well as gold and a Wand of Binding belonging to Warden Ramos Stormforged. They learned the dwarf was also named "Voice", taken in due to their association with the Fold, as well as some dirt indicating the Hollyhock was an informant on the Glitterati. After intentional poisoning themselves with medicine in their food, they were able to get to the hospital bay and trade the records to Prisoner 13. The Dwarf-Door Tattoo Key was located on her body, which Elle was able to trace with her forging skills.
Their plan failed right at the end when Nessa, who had set the surveillance tower to become a beacon, had no legitimate way to rejoin the rest of the Crew in the prison's hospital. She descended the tower, panicked, and ultimately had to dash for the doors. Though she was able to lock out those chasing her and Mercy was able to light a beacon to signal to their ship, the Sorcerer nearly killed himself with a wild magic surge. Warden Ramos put Bleak End on lockdown, allowing archers to magically see through their Dust of Disappearance, and they had to endure a near-deadly storm of arrows as they slowly drifted away in a rowboat.
Through illusions, healing, and Mercy's Wind Fan, they were able to board the Jolly Dodger just barely alive. With no other ships on Aone Island to chase them, the Crew managed to sail off, once again as successful thieves. They made their way back to Farrozandmar, where Mercy told Hollyhock of their knowledge of her status as an informant, but promised to keep her secret. The Crew also made friends with Sassafras Flashlashes, who accompanied them back to the Pixis Palace. There, they were strongarmed into assisting the Glitterati in their campaign into the Undermire, and Don Coriander assembled his entire gang to travel to the Faeriefort.
Alongside Sassafras, Merben, and Snapdragon, the Whistledrop Crew fought off Lizardfolk hunters in the Murkmire Marshlands, with Mercy accidentally going into a Wild Magic overdrive and summoning the Unicorn Hallannaë temporarily amongst myriad other effects. Eventually, they made it to the Faeriefort, where they convinced Laceleaf Flashlashes to let them pass through Sprite's Hollow and into the Deepways. Down there, Punmiri and Elle found symbols relating to their previous experiences with the Fold, while Mercy used his Infernal ability to read a prophetic poem; he also encountered many symbols of Virathul, seemingly resonating with Wild Magic.
They reached the Undermire Dwarf-Door, but an ambush was waiting: Prisoner 13 had contacted Vex and Volition, who had set up an ambush. A battle turned into a massacre, and the hundred-strong Glitterati were reduced to a mere handful. Though Mercy killed Fold scouts with electric blasts, Volition invoked a symbol of Wild Magic that knocked him out. When consciousness finally returned, the wild magic sorcerer found himself restrained to prevent spellcasting, his fingers clamped down while electricity coursed painfully through his body; he had become a new project of the Fold.