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|This section contains spoilers of an episode, movie, or book.|
The Sparrow Scouts are in Gorrill Gardens to count the Woff during their annual migration. Hilda and Frida discuss the woff, including how their migration patterns are still a mystery to everybody, and how a white woff is a sign that magic is extra strong that lunar cycle. Then, without warning, the bell in the tower nearby begins to ring, startling the scouts and frightening the Woff. The Woff become disorientated and some even crash into the ground. The Sparrow Scouts are able to help them get back into the air.
When Hilda gets home, she finds her mum working on a new project. However, Johanna finds it difficult. Once Hilda gets to her room, she finds Bartell of the Lost Clan waiting for her. Apparently, the unexpected bellringing every hour is disturbing their lives as well. Among other things, their livestock has stopped producing. Tontu joins the conversation, since Nisse are also being disturbed by the bell ringing. Bartell is willing to go to war to silence the bell, but Hilda decides to talk with the bell keeper first.
When she gets to the bell tower, she is in for an unpleasant surprise; the bell tower has been automated. A mechanical bell keeper rings the bell every hour. The human bell keeper finds Hilda snooping around. He tells her that this mechanical bell keeper is just the first; on orders of Erik Ahlberg, all bell towers have been equipped with one, controlled from within a central bell tower, and soon they will automatically ring all the bells 24/7 to keep the trolls away. It also has put him out of a job. Hilda is naturally upset because of this news, and vows to stop it.
When she gets home, she finds her mum asleep on her drawing board. The project Johanna has been working on is for the new bell tower, and among the reference material she received is a blue print of the tower. Hilda takes this blue print, so she, David, Frida, Bartell, Alfur and Tontu can come up with a plan. During the day of the ceremony, the Lost Clan will attack the bell tower to distract the Safety Patrol, after which Tontu can let Hilda and Frida into the tower through Nowhere Space, and the girls can sabotage the central control system. David will stand guard. The plan will be executed on the day the system is officially taken into use, since Erik Ahlberg’s speech will provide a nice distraction. David dubs their plan “Operation Deerfox Thunder Team”.
On the day of the ceremony, Hilda convinces her mum to visit the ceremony, then excuses herself and joins her friends. The plan succeeds and Hilda and Frida sabotage the main system, but it turns out there is a backup system in place. Frida deduces they could try to disable the bells from the main control panel in the top of the tower. Hilda and Twig thus try to reach this room. They find the door locked, but get some unexpected help; the bell keeper himself comes to their aid. He has been listening in to their plan with his own walkie talkie, and he too loathes the new system. Once in the room, it is too late to shut off the system since it has already been primed, so Hilda improvises and quickly puts all the bells on maximum volume. This overloads the mechanical bellringers, and they all short out. It also causes the bell in the central tower to dislodge. It smashes through the window, and falls on top of Erik Ahlberg, trapping him inside.
Hilda returns to her mother and apologizes for having missed the ceremony. The Lost Clan celebrate their victory while peace returns to Trolberg. The Woff continue their migration, and a white one actually shows up. But with the system down, Ahlberg orders all bells to be tested, including one underwater near Cauldron Island. When the bell is rung, something awakens underneath Cauldron Island.
- Trolberg Safety Patrol
- Sparrow Scouts
- Mr. Ostenfeld (cameo)
- Ms. Hallgrim (cameo)
- Hilda has mastered riding a bike; something that she had trouble with back in “Chapter 6: The Nightmare Spirit”.
- This is the first time Johanna’s white shirt is shown, the second will be Hilda and the Mountain King.