FunFrock's secret fortress is FunFrock's main fortress, and headquarters when he is in the north hemisphere. It is also the place where the clones are made. It is located in Fortress Island and it was constructed around the Stone of the Septentrion, since it couldn't be destroyed. The building is very well guarded by soldiers, clones and a tank. Behind the fortress there's a passage to Polar Island that FunFrock ordered to be made.
To access the fortress Twinsen has to be helped by the local rabibunnies, but they will only help him if he destroys the Teleportation Center first. If he has done it, he has to kill the guards and a rabibunny will dig a path to the passages under the fortress.
Going through the underground tunnels, Twinsen fighst a monster and goes through a training pool, until he finally reaches a cell with Zoé in it, but when he releases her, a cage falls upon him, and FunFrock appears, revealling that it's only a clone of Zoé and the real one is held at the Well of Sendell.
Twinsen then wakes up in a cell inside a part of the building that is very similar to one of the Citadel. Twinsen escapes and finds a seal of Sendell in the cloning room, which leads to a cave where the Stone of the Septentrion is. After Twinsen pours a little of the clear water from his flask, the stone explodes, destroying the whole fortress. Luckily, Twinsen escapes just in time. After that, he can use the path behind the fortress to acces Polar Island.
- In the exterior of the building, Twinsen can see Zoé inside a cell and can talk to her. The dialogue is a bit different depending on whether Twinsen is looking for the Teleportation Center plans or not. Afterwards shots are heard, she cries and taken away. It is not clear if it's herself (later replaced by the clone), or her clone.
- If Twinsen lets the nurse sound the alarm after already having sabotaged the teleportation center, instead of a clone, Raymond the Elf will appear.