Original: Their old priestess, Kaede, recognizes Kagome as the reincarnation of her sister Kikyo; when the centipede demon returns, Kaede realizes that the Jewel of Four Souls has also been reborn in Kagome's body.
Simplified: She meets Kaede, an older one because 50 years passed in this world after what happened to Kikyo. Kaede finds out that Kagome is the reincarnation of her own sister, and helps her keep the real shikon no tama that Kagome suddenly found in her body.