As for Casey, he bid Chicago farewell earlier this season, setting off to Portland, Oregon, to look after the sons of his late best friend. But he’ll pop up again in Fire‘s May 25 Season 10 finale, coming back “to support Severide through what will be a very topsy-turvy wedding” and to spend time with long-distance girlfriend Sylvie Brett (Kara Kilmer) as that wedding “puts a spotlight on their [own] situation,” co-showrunner Derek Haas has revealed.