Ben 10 S03E32 - Roundabout (2)

Gwen, Grandpa Max and Phil tracked down Ben in an underground lab. They try to dissuade him from joining forces with Forever Knight. With Ben's help, Forever Knight opened a time portal to travel back in time. He wants to prevent the signals sent by aliens to Earth to make contact to be answered. Because then there would be no Omnitrix watches and therefore no aliens