Gate Key

"But Gates are unstable-that's why they appear and disappear all the time. So I used the principle behind my Telepod device...to create this Gate Key! It's what's locking the Gate in place. "

— Lucca talking to Marle about the Gate

The Gate Key is device Lucca invents in Chrono Trigger. It is used to travel through time via the Time Gates.

Lucca explains that the device does not itself allow the party to time-travel. Instead, the Gate Key stabalizes pre-existing temporal anomalies, creating the temporary passages that the party uses to cross from one era to the next. The exact manner that Lucca achieves this technological wonder is never clearly explained; however, it is possible that Lucca's work on the Telepod gave her insight into the science of dimensional and temporal teleportation. The Gate Key is arguably the most powerful of Lucca's inventions.

During the events in Prehistory surrounding the party's search for the Red Rock, the Gate Key is lost, leaving the party stranded until it is recovered. It is found in the posession of Azala, who does not believe that it could have been created by any of the 'primitive' humans. After the defeat of Nizbel, Azala's champion, the Reptite leader angrily returns the Gate Key, vowing revenge on Crono and his allies.

In one of Chrono Trigger's many endings, if the Epoch has been destroyed, the party leaves Present using the Gate Key.