Complex sentence: Juliet comes to support Justin at the Russo family's wizard competition, where she and Mason meet and both acknowledge that no hard feelings left from the events that took place in "Wizards vs. Werewolves".
Split into simpler sentences: Juliet comes to support Justin at the Russo family's wizard competition. She and Mason meet once again in that occasion and both acknowledge that no hard feelings left from the events that took place in "Wizards vs. Werewolves".