The TARDIS lands in the year 100,000 BC, and he meets his first incarnation in the jungle and they psychically link (giving the Eighth Doctor his memories up to that point in his life). The Eighth Doctor stops his other self from killing a caveman who was slowing their party down. The First Doctor explains that he must get away before the "time bubble" his Eighth self is in bursts and starts to damage the timeline. The Eighth Doctor then leaves.
