The NCIS season 23 finale is just around the corner and fans of Special Agent Timothy McGee need to brace themselves for a wild ride ahead. "One of our leaders, Mr. Timothy McGee, is in for a big surprise at the end of the season," Diona Reasonover, who plays forensic scientist Kasie Hines, exclusively told Us Weekly ahead of the finale, which airs on Tuesday, May 12. She teased that McGee, played by Sean Murray, is going to have "his relationship and his heart tested in a way that we are not going to see coming.