VIII. Lightspeed Rescue
The five Rangers would be joined by Captain Mitchell’s (long thought to be dead) son, Ryan Mitchell. Together, the six Rangers would prevail against the demon forces time after time, culminating in a final showdown where, in the Power Rangers tradition, much of the weapons and other equipment that was used by the Power Rangers over the series was destroyed.
In addition, Lightspeed Rescue featured a cameo reappearance of characters from Power Rangers: Lost Galaxy, when the villainess Trakeena comes to Earth to destroy it and the Lightspeed Rangers team up with the Galaxy Rangers”
-Taken from: http://powerrangers.wikia.com/wiki/Lightspeed_Rescue