Justin Hartley's character, Colter, is on a mission to find Bobby's friend before it’s too late on a new episode of Tracker. In Us Weekly's exclusive clip from the Sunday, March 31, episode, Colter reunites with Bobby (Eric Graise) to help him find his missing pal. "Why would Sun leave out the back when she could just come out the front?" Colter notes to Bobby, who replies, "Sometimes people use it as a shortcut to the bus stop, but she doesn't usually take the bus." Colter asks whether Bobby's friend did "anything else unusual" before her disappearance. Justin Hartley. Ed Araquel/CBS Justin Hartley’s Insightful Quotes About ‘Tracker’: From the Stunts to Potential Love Interests "I heard she got into it with one of the fighters. Some guy named Dake," Bobby recalls. "I tried [to ask him], but it didn't go so well. You have to put in a lot of time and effort to get the respect of the guys here." Bobby shuts down Colter's theory that Sun could have been scared of Dark, adding, "No. Sun isn't afraid of anybody. But he is in there working so we can ask him what's up. Or you can ask him." Colter, however, is focused on using his detective skills as he and Bobby look around an alley. It doesn’t take long for Colter to spot a clue, which turns out to be a piece of a broken phone. In response to a question about Sun's phone of choice, Bobby replies: "[She uses] a burner, always. They are cheap and you don't have to use your real name. It's one of the things we have in common. She has a very healthy distrust of government intrusion." Spring TV Preview 2024: Inside Must-Watch New and Returning Shows Bobby dials Sun's number, and that leads the duo to a bloody phone behind a dumpster. According to the synopsis, the newest episode of Tracker will show Colter, Bobby and Reenie (Fiona Rene) racing against time to track down a talented MMA fighter who disappears while trying to solve her family’s trouble with their visas. Ed Araquel/CBS Colter has been solving a wide variety of cases on the first season of the CBS series. The procedural, which premiered in February, is based on Jeffery Deaver's novel The Never Game. Hartley — who is also an executive producer — teamed up with This Is Us producer and director Ken Olin on the project. All the Times ‘This Is Us’ Cast and Crew Reunited on a Project After the Show Ended "I'm excited about it. It's been a long time coming. Ken Olin and I built this show from the group up years ago. We've been at this for years, through a pandemic, and a strike, and on and on," Hartley, 47, told Entertainment Tonight in February. "We poured our hearts and souls into this thing and started working on this what seems like forever [ago]. It's a labor of love for sure. I'm really proud of it and just happy to finally get a chance for people to see it." Tracker airs on CBS Sundays at 9 p.m. ET. New episodes stream the next day on Paramount+.