Detective Charlie Hudson on "Hudson & Rex," played by John Reardon, was written out of the show in Season 7 because the actor was diagnosed with tonsil cancer and had to step away from filming for treatment. The character's absence in the storyline is explained by Hudson being on a mission off-screen. John Reardon has since recovered and been medically cleared to return to work, raising hopes for his return in Season 8. During this period, a new detective named Mark replaced him in the team. As for Rex, the original canine actor Diesel vom Burgimwald, who played the police dog Rex, died unexpectedly in August 2024 after seasons 1 through early 7. The role of Rex was then taken over by Diesel's nephews and cousin from season 7 episode 3 onward, with other related dogs performing stunt scenes. In the show, Charlie Hudson and Rex are a detective and his highly trained K-9 partner who joined forces under tragic circumstances when Rex's former handler was killed. Their partnership is central to solving crimes in the series.