The original X-Babies were X-Men de-aged by Mojo, they were saved by the New Mutants. When the X-Men went missing during the Fall Of The Mutants Mojo created the X-Babies again, this time as their own entities. However, he decided they were a bad idea and was about to have them destroyed when they escaped.
The X-Babies went to the UK (Earth), however Mojo sent “The Agent” (a brainwashed Ricochet Rita) after them. The X-Babies were aided by Shadowcat and Excalibur, but had to agree to work for Mojo so that “The Agent” would be released from her brainwashing.