"Castle" season 8 episode 13 is almost here. The official synopsis from The Futon Critic reads: "Beckett and the 12th Precinct look into the murder of an English as a Second Language student. But when the victim's class won't talk to the police, Castle goes undercover as a French Canadian immigrant and learns that the victim was more than he seemed."

In the episode's promo trailer, Castle is seen in action as an undercover ESL student. He pretends to be a French-Canadian with a decent accent trying to learn English in the class, while digging some information from the class itself. He introduced himself to the other students, including the woman from Senegal who converses with him in pure French.

The second promo trailer is a sneak preview of a scene where Castle is complaining to Alexis and Hayley in his own Private Investigation firm to find more challenging cases to solve.

Meanwhile, here is the rundown of the previous episode, titled "The Blame Game."

A TV news producer was found dead in her own apartment. Castle went to an address right away without learning more. He ended up in a classroom with three strangers after he passed out.

The three strangers said that they all got the address through a text message. Castle realized that the culprit must be playing a game before killing them.

The room they were trapped in had clues that sent a message saying they had to choose whether to play or die. Some clues led to life-threatening situations like when Todd got stung by a bee after he removed a fire axe from its glass casing.

One of the clues left was a handgun with a note that the last man standing will get his freedom. They later realized that their loved ones, including Beckett, were also captured in a separate room.

After playing the game and refusing to play the game, they discovered that Todd was the culprit. Meanwhile, Castle and Beckett saved the day.

"Castle" season 8 airs every Monday at 10 p.m. on ABC.