Tracker's Season 4 Premiere Is Tomorrow - the Finale Recap You Need Before Colter Returns

Colter Shaw is back on the trail tomorrow. Tracker returns for Season 4 on Sunday, October 4 on CBS - and if you have forgotten where the Season 3 finale left things, you are not alone. The show's biggest mystery is still hanging, and the new season is about to make it worse.

First, the logistics. The Season 4 premiere, titled "Safe Harbor," airs Sunday at 9:30 p.m. ET, following Marshals during CBS premiere week - a temporary slot. Starting October 11, Tracker settles into its regular 9 p.m. Sunday home. In the premiere, Colter's search for a teenage boy's missing father pulls him toward a dangerous criminal operation at the Port of Los Angeles: a classic Tracker case, a missing person, a dangerous trail, and Colter working it alone.

The secret the audience knows and Colter doesn't

But the real story is the one simmering underneath. The Season 3 finale ended with Colter and his brother Russell uncovering a web of government experiments - and with a bombshell aimed squarely at the Shaw family. McIntyre, played by Glenn Morshower, blackmailed Russell into taking on a shady job with a simple threat: do it, or Colter learns what is in a file detailing what their father did to Colter as a child. Russell accepted. He told Colter nothing.

That puts the show in uncharted territory. For the first time in its run, the audience knows something Colter does not - we watched Russell take the deal, and we know the secret he is keeping. Justin Hartley has said the show will sit with that imbalance this season rather than resolve it immediately, calling it the first time viewers have ever been ahead of his character. Whatever their father did, Hartley believes the brothers' bond is strong enough to survive it - and that Russell is keeping the secret to protect Colter, not betray him.

Help is on the way, though not as fast as fans might hope. Jensen Ackles returns as Russell in Episode 5, and Hartley has promised the reunion happens "in a big way": the brothers join forces over a dire case involving one of Russell's friends - someone who emphatically does not want to be found. Beyond that, Season 4 is digging deeper into Colter's tangled history with his father, the doomsday-survivalist Ashton Shaw, whose secrets have been the show's slow-burn engine since the pilot. And there is one more ghost in the machine: Dory, Colter's other estranged sibling, has not been seen since her fleeting Airstream reunion in Season 2, and her absence is starting to feel significant.

New case, old wounds, and a brother keeping the biggest secret of all. "Safe Harbor" premieres Sunday, October 4 at 9:30 p.m. ET on CBS.