Simplify the following text for a Grade 8 native English-speaking person.
Original: The Cybermen returned in episodes 5 and 6 of the 2006 season of the new series , in a two-part story set on an alternative Earth .
Simplified: The Cybermen returned in episodes 5 and 6 of the 2006 season of the new series , in a two-part story set on an alternate Earth .