TV THIS WEEK: The Flash's finale, Between's premiere, and more!

It's a bit of a light week on the TV front, since so many of our shows have already had their season finales, but there's plenty of excitement. This week we say goodbye to both The Flash and Supernatural in the fall, get a Simpsons Halloween marathon and witness the premiere of a new Netflix sci-fi series.

Check out the week in TV below. What's on your watchlist?

Highlights of the Week

The Flash (CW) Tuesday, 8 p.m. - "Fast Enough"

Season finale! - At last, we've reached the end of the wild first season of The Flash, and we already know a second one is on the way. Back before things kicked off, we weren't really sure what to expect from this series, and in some ways it was a little worrying. Many fans (including myself) felt from the start that Flash shouldn't be Arrow, and worried that the grim vibe of so many of Oliver Queen's adventures would transfer to much into Barry Allen's. Turns out we didn't have much to worry about in that area, and what followed was a whole season of what might be the most-comic-book comic-book series on TV (at least until next season). We got superspeed, lots of supervillains, supervillain team-ups, time travel and even Gorilla Grodd all over the course of 21 episodes, and the 22nd promises to deliver even more crazy adventures for the Fastest Man Alive. This week, Barry faces a life-changing choice and Firestorm returns for the final fight. Check out a preview below.

Supernatural (CW) Wednesday, 9 p.m. - "Brother's Keeper"

Season finale! - It wasn't so long ago, round about season seven or so, that it seemed possible that Supernatural didn't have much steam left in it. Ratings were slipping, the show'd been on for years, and it felt like the Winchester brothers might finally be driving off into the sunset. Then the show went on, the ratings actually got better, they stayed better, and here we are at the end of season 10 with an 11th already on the way. The show doesn't wield the ratings power of its earliest seasons anymore, but it does wield one of the most enthusiastic and devoted fanbases of any series on TV, and that plus a lot of continued inventiveness in the story department has managed to keep it on the air. Bring on season 11. This week, Dean makes a shocking decision regarding the Mark of Cain. Check out a preview below.

Treehouse of Horror Marathon (FXX) Thursday, 8 p.m. 

Marathon time! - So, you may have noticed that our TV schedule is shrinking a little bit, and that's because we're in that somewhat awkward in-between time when the spring shows are ending and the summer shows aren't out in force just yet, but that doesn't mean there's nothing to watch. This week, FXX takes its complete Simpsons library and puts it to good use with a four-hour marathon of various "Treehouse of Horror" Halloween specials from the show, including the original. We have no idea why they're doing it in the middle of May, but hey, enjoy it while you can.

Between (Netflix) Thursday, Streaming - "Episode One"

Series premiere! - Netflix just keeps branching out with original and exclusive series, and the latest is the genre drama Between. It's the story of a town in which everyone over the age of 21 begins to die of a mysterious plague, leading to a quarantine that leaves the remaining young people (led by Sam & Cat star Jennette McCurdy) to try and solve the mystery of what's happened. Unlike most Netflix shows, this one will be streaming week by week, until all six episodes have aired, so you can't binge this time. The concept's definitely intruiging, and we're looking forward to seeing how this plays out. Check out the trailer below.

Game of Thrones (HBO) Sunday, 9 p.m. - "The Gift"

Now that we're at more-or-less the halfway point for Game of Thrones season five, let's take a look back and see how the show's done this year in terms of ratings. It's been HBO's top series for a while now, and other than stuff like The Walking Dead it's easily one of cable's biggest shows, but we've been wondering ever since the numbers really started exploding during season three just how long the show would sustain it. It's a complex beast, after all, and one that certainly has power to drive some viewers away with things like character deaths and rape scenes, so how long until we start to see signs of Game of Thrones fatigue? Apparently, not yet. The show debuted this year with 8 million live viewers, the best single-episode audience it's ever had, and that's not even counting DVR, streaming and, well, piracy. Ever episode since has remained firmly above the 6 million viewer mark, and last year the back half of the season put up better numbers than the front, so the best ratings days could lie ahead. We know the show's already coming back for season six next year, and if Game of Thrones keeps this up, season seven is a guarantee. Check out a preview of this week's episode below.

Monday, May 18

Monday is, for the first time in months, pretty quiet this week, but you can use the time to catch up on everything crowding up that DVR.

Tuesday, May 19

The Flash (CW) 8 p.m. - "Fast Enough"

Read more in our Highlights section above.

iZombie (CW) 9 p.m. - "Mr. Berserk"

Liv and Clive investigate the murder of a journalist who was working on a story that linked psychotic episodes in a small number of consumers to a popular energy drink. Meanwhile, Ravi tries to help Major, who continues to believe that he's going crazy.

Wednesday, May 20

Supernatural (CW) 9 p.m. - "Brother's Keeper"

Read more in our Highlights section above.

Thursday, May 21

Adventure Time (TOON) 7:30 p.m. - "Water Park Prank"

After rescuing Princess Orangutan from Daddy Sad Heads, Finn and Jake head to a post-apocalyptic water park for a day of fun.

Treehouse of Horror Marathon (FXX) 8 p.m. 

Read more in our Highlights section above.

Wayward Pines (FOX) 9 p.m. - "Don't Discuss Your Life Before"

Ethan is helped by Beverly as he continues looking for clues to figure out how Secret Service agent Bill Evans' body ended up in an abandoned house; and he gets answers to the mystery of why people in Wayward Pines always have to answer their phones. Elsewhere, Theresa and Ben decide to take their search to Idaho.

Lost Girl (Syfy) 10 p.m. - "Clear Eyes, Fae Hearts"

Bo and Tamsin go undercover in the world of college football to investigate a murder that could expose the Fae.

Olympus (Syfy) 11 p.m. - "Love and Time"

Hero learns that the only way to unlock his destiny is by taking the life of someone he loves when he and Medea travel to the Temple of Aphrodite; at the same time, Medea's sister, a Magi warrior and cold-blooded killer, shows up to reclaim her sacred ring.

Between (Netflix) 11:30 p.m. 

Read more in our Highlights section above.

Friday, May 22

The Messengers (CW) 9 p.m. - "Metamorphosis"

All of the Messengers search for the Second Horseman. Meanwhile, Erin realizes her gift comes at a cost; and Alan and Vera are determined to unearth the secrets of the genesis stone.

Saturday, May 23

Orphan Black (BBC) 9 p.m. - "Certain Agony of the Battlefield"

No synopsis available.

Sunday, May 24

Game of Thrones (HBO) 9 p.m. - "The Gift"

Read more in our Highlights section above.

Penny Dreadful (Showtime) 10 p.m. - "Evil Spirits in Heavenly Places"

Lyle reveals that the Verbis Diablo relics tell a very dark and disturbing story that affects Vanessa; Rusk interviews the survivor of the attack at the Mariner's Inn; Hecate tries to get closer to Ethan; Angelique and Dorian's romance grows. Back at Sir Malcolm's mansion, Vanessa, Ethan, Sir Malcolm, Sembene and Lyle carry on their evening as something evil lurks within, ready to strike.

Salem (WGN) 10 p.m. - "Dead Birds"

Countess Marburg's Achilles' heel is revealed.

(Episode synopses via TV Guide)

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