Maintenance Hub

The Maintenance Hub is a room inside of the Old Clockworks in Luigi's Mansion: Dark Moon. It is accessed by taking the door on the left on Floor B1 of the Service Elevator or by taking the door on the right inside of the Synchro Gantry. It is a small room. In the middle of the room is a large gear that only turns once the hidden gear in the Crank Room has been revealed. A zipline is used to allow Luigi to travel between the entrances to the Synchro Gantry and the Service Elevator. On the ground below, there is nothing but sand, mice, and a hidden Treasure Chest. The door on the left takes Luigi back to the Synchro Gantry while the door on the right leads back to the Service Elevator. There is an invisible door to the north that takes Luigi to the Crank Room when shone with the Dark-Light Device.

During C-5: Piece at Last, Luigi must go to the Maintenance Hub to reach the Synchronization Room where the Toad assistant is. However, the way to the room is locked, so he must go north into the Crank Room to find a key. After finding the key, he must head back to the Maintenance Hub and into the Synchro Gantry. After he rescues the Toad and when they return to the Maintenance Hub, they are attacked by three Greenies wielding mallets and a piece of metal as a shield.

Only during C-5: Piece At Last and C-Bonus: Outlandish Interruption, Luigi should drop down to the lower floor of the Maintenance Hub. In the middle of the room, there is a Treasure Chest hidden away by Spirit Balls. Using the Dark-Light Device, Luigi can reveal the Treasure Chest that releases a ruby once it has been investigated.