The Dutton family will stop at nothing to avenge the death of patriarch John Dutton.

On the Dec. 1 episode of the hit show Yellowstone, Kayce, played by Luke Grimes, goes to the most extreme length seen from the character to uncover the truth behind his father’s murder.

In the previous episode, viewers learned that John’s death wasn’t a suicide. John (Kevin Costner) was killed in his home when a group of masked men dragged him from bed into the bathroom where he was injected with a drug in between his toes that left him unconscious.

The men made it appear as a suicide by shooting John, placing a bottle of Oxycodone near his body and leaving the gun in John’s hand.

Audiences learned that Sarah Atwood (Dawn Olivieri) was responsible for hiring the hitmen to kill John, and after having a brawl with Jamie (Wes Bentley) in last week’s episode, she drives away and is shot in the head.

The show picks up in episode 12 with Kayce and his sister Beth (Kelly Reilly) learning that their adopted brother Jamie (Wes Bentley) is being investigated after detectives arrive at Jamie’s house inquiring about Sarah’s death.

As Kayce and Beth work on a way to stop their brother from talking to authorities and subsequently revealing their father’s secrets, another death takes place on the ranch.

Just hours after confessing his love to Teeter, ranch hand Colby (Denim Richards) comes to the rescue of Carter, a teen taken in by the Dutton ranch, when Carter is trapped and cornered in a stall by a troubled horse. As Colby allows Carter to escape, the horse kicks Colby directly in the chest, killing him. Carter shoots the horse but there’s no saving Colby.

Colby appeared in seasons 1 and 2 before becoming a regular in season 3.

At the end of the episode, the drama returns to John’s death as Kayce packs up and leaves for the night to do “what’s best for the ranch.”

After discovering the identity of the individual linked to the shadow organization that staged John’s suicide via an old military contact, Kayce tracks down the murderous man to his daughter’s soccer game.

As the man and his daughter are about to drive away after the game, Kayce jumps into their car and holds the daughter at gunpoint, demanding the man drive. He threatens the murderer saying he knows where his family works and lives and hits the man over the head with his gun as he says in a menacing voice to the girl, “You should cry.”

Kayce threatens to kill both of them if they look back as he jumps out of their car.

There are two episodes left of the hit series, which is ending after 5 seasons. Fans waited nearly two years since the midseason finale for the Duttons to come back on screens. But this summer they learned that Costner would not be continuing in his role.

“Him not coming back felt like, ‘Okay, we’re going to have to land this plane now for real,’” Grimes told PEOPLE of Costner’s exit. “I think the patriarch leaving was always going to be part of the story. That’s always where it was headed is like, what do these kids do? What does this family do when their rock is gone?”

Although he acknowledges the “drama” that predated Yellowstone’s return to filming — including scheduling conflicts between Costner’s Horizon: An American Saga and Yellowstone that led to the Academy Award winner bowing out of his role on the show in June — Grimes adds that he felt as though “it was always going to go that way.”

“Whatever the circumstances may be, [it] definitely felt like, ‘Okay, we’re coming in for a landing,’” he says of Costner’s absence. “It definitely felt different.”