After traveling to the Ocean Palace and witnessing the awakening of Lavos, Crono, two of his friends, The Prophet, Schala, Janus, and Queen Zeal are transported to an alternate dimension inhabited by the alien parasite. Attempting to do battle, the party is immediately devastated by the twin might of Lavos and Queen Zeal. To save his friends from death, Crono accepts the blow. Schala, using her Pendant, transports the party safely to Last Village where they witness the destruction of the Ocean Palace and the Fall of Zeal.
Traveling to the End of Time to seek advice from Gaspar, he supplies them with the C. Trigger and asks them to seek Belthasar in the year 2300 AD. The Guru's Nu advises the party to find a Doppel Doll. Once acquired, they scale Death Peak where the C.Trigger shatters, teleporting them back to the exact moment before Crono sacrificed himself, and they replace him with the Doppel Doll. Ever-grateful, he rejoins the party again.
The Doppel Dolls won by each character are found as follows:
Doppel Doll, or "Doppel-Kun" in Japanese, is a portmanteau of the words Doppelganger and "Doll". The suffix "-Kun" in Japanese is an affectionate honorific, usually applied to young men.