9 things you need to know before the 'True Detective' season finale

Warning: spoilers ahead if you aren't caught up on the season

The thing about the police procedural is you have to have a grasp on a lot of names and events to really follow the plot. Season 2 of "True Detective" has both in mass quantities.

So leading up to the season finale on Sunday, here are some major points from the show you should be familiar with.

1. Here's the deal about those blue diamonds.

Blue diamonds were found in murdered city manager Ben Caspere's safe deposit box in episode 3. In episode 6, Woodrugh looks into the diamonds and learns they were robbed from a jewelry store during the 1992 LA riots, with the mom and pop owners murdered. As the store was looted soon after the robbery, the diamonds are untraceable.

Woodrugh has also found that Lt. Kevin Burris...

and Detective Teague Dixon...

were working under Vinci Police Chief Holloway...

at the time of the riots and the jewelry store was in their district. Caspere also worked in the same department. That leads Woodrugh (Taylor Kitsch), Velcoro (Colin Farrell), and Bezzeridies (Rachel McAdams) to conclude that the officers were all working together. They stole the diamonds and Caspere helped move them.

The money they got for them went to Vinci mayor Austin Chessani...

which then led to them being the movers and shakers of one of the most corrupt cities in LA county.

2. Why this picture is so important.

These are the kids that were orphaned due to their parents being killed in the diamond heist by the rogue cops during the '92 riots. Velcoro and Bezzeridies believe they met one of them. They think Erica, who worked in Caspere's office, may in fact really be Laura, one of the orphaned kids. They are currently trying to track her down.

3. Why Ben Caspere really died.

Caspere holding onto those diamonds turned out to likely be what got him killed. Dixon was checking up on where they could be long before Woodrugh started. Caspere's house was probably tossed by Burris or Dixon looking for them. Then there's the Hungarian prostitute, Tasha, who was taking photos of Caspere at the high class sex parties, like the one Bezzeridies infiltrated in episode 6, in the hopes to blackmail him. She was tortured and killed in a cabin in the woods upstate.

The same was likely done to Caspere by the hands of Burris or Dixon when he didn't give up the diamonds. The final piece of evidence for a 23-year-old double murder. Though Bezzeridies is curious why they would kill Caspere when that's what launched the investigation in the first place. Hopefully that will be answered in the finale.

4. What we now know about that insane shootout.

We were led to believe that the shootout that occurred at the end of episode 4, in which a pimp named Ledo Amarilla...

was suspected of being Caspere's murderer and was killed in the shootout, was the end to the Caspere case. Though months later Woodrugh, Bezzeridies, and Velcoro were pretty certain they didn't really close the case, it was confirmed in episode 7. Woodrugh learned that the shootout was a set up, as Burris had arrested Amarilla in 2006 and released him soon after interrogation with no notes kept about any of it. Amarilla and Dixon, who was also killed in the firefight, cuts down the number of people who really know the motive of the Caspere murder.

5. State Attorney Katherine Davis is dead.

One of the only people who actually was doing something to clean up the city was State Attorney Katherine Davis. But as it often goes with these shows, the ones out for justice get killed at some point, and that's what happened in episode 7.

Davis was the one who made a special task force of Woodrugh, Bezzeridies, and Velcoro to investigate the Caspere murder again following the shootout in the hopes of uncovering collusion between Mayor Chessani and California Attorney General Richard Geldof...

who is now running for governor. Now with Davis out of the picture - killed, Velcoro believes, with one of his guns - he and Bezzeridies (due to stabbing of the security guard at the sex party at the end of episode 6) are now considered fugitives. Leaving Woodrugh the only one able to roam free to investigate things.

6. Woodrugh is dead.

But that stopped at the end of episode 7 by the gun of Burris. At first Holloway tried to blackmail Woodrugh with pictures of him with another man. But after Woodrugh was able to shoot his way out of that situation, the backup plan seemed to be Burris killing Woodrugh. (Guess we'll never get the story behind those scars on his body.) With Woodrugh now dead, Bezzeridies and Velcoro have to work in the shadows as the law is after them.

7. Velcoro and Bezzeridies are finally a thing.

While in a cabin upstate waiting for Woodrugh, Bezzeridies and Velcoro finally give into what we had assumed all season was going to happen and have sex. We'll see in the finale if that plays into how the season concludes.

8. The person behind the crow mask.

In episode 2, Velcoro investigates Caspere's secret house that he brought prostitutes to. While checking it out a person wearing all black and a crow mask shoots him with what we find out in the next episode were rubber buckshots. The same person with the mask was driving around Caspere in the first episode. Seeing it's likely Burris or Dixon who killed Caspere, it's also likely one of them is the man behind the mask. Looking at the size of the person that shot Velcoro, it looks more like Burris' build. Through the season we got more hints, like that the cop that gave Irina the prostitute Caspere's belongings was described as "thin, white" and "a cop." Sounds like Burris more than Dixon. Also, it was Burris who had a lot of questions for Velcoro when he left Vinci PD following the shootout. And with Dixon now dead all fingers point to Burris.

9. Frank Semyon is preparing to hijack a big money drop.

The whole season Frank Semyon (Vince Vaughn) has been trying to figure out who killed Caspere, his partner in the creation of a high-speed rail line through California. With Caspere dead, so was Semyon's dream to go legit. So he had to turn back to his casino in Vinci and running clubs where he takes a percentage of drugs being sold and prostitution.

But in episode 7, while interrogating his underling Blake, who has turned on him...

Semyon finds out that he was always the patsy.

Osip Agranov, a Russian gangster who was supposed to go in with Semyon on the rail line...

double crossed him and has teamed with Chessani's son, Tony, to take over the rail line...

Tony will also take over his father's position as mayor, giving Agranov power of Vinci. Agranov has also taken ownership of the casino and clubs, pushing Semyon out of everything. Blake also revealed to Semyon that there is to be a drop of $12 million from Agranov to Tony. Semyon kills Blake, cleans out the money in the safes at his properties and lights the buildings on fire. You better believe Semyon plans to be at that money drop.