“Arrow” Season 5 is going to be very different. At the end of Season 4, Felicity helped Star City avoid a nuclear bomb, Thea and Diggle decided to step back from the team, and Oliver was elected mayor. Though Damien Darhk was defeated, Star City is never low on evil criminals. Oliver will face new villains in Season 5, but he’ll have a lot of personal challenges as well. Here’s what you need to know about the CW drama before Wednesday’s premiere:

1. The New Team — Oliver (Stephen Amell) might not want to admit it, but he and Felicity (Emily Bett Rickards) are the only original team members left standing. He’ll add Curtis/Mr. Terrific (Echo Kellum) to his lineup, as well as a few amateur vigilantes he inspired. Evelyn/Artemis (Madison McLaughlin), Rene/Wild Dog (Rick Gonzalez), Adrian/Vigilante (Josh Segarra) are the new heroes on the block.

2. Felicity’s Guilt — After rerouting a nuke to Havenrock and killing thousands, Felicity will have a tough time dealing with that responsibility. “Coming out of that, trying to figure out what that means and trying to figure out what kind of person would do that,” executive producer Wendy Mericle told TV Guide, “and the complexity of the decision and how it was made, will really complicate [things] and give her what we hope is a very rich storyline this season, in terms of how she will deal with the guilt of that.”

3. Olicity — Don’t expect much romance from Oliver and Felicity. “They’re both in crisis mode. Oliver’s got two really big jobs, and [Felicity] is spinning out about Havenrock,” Mericle told TVLine. “Until they’ve gotten some clarity for themselves, there’s not much room for the relationship side of things.”

However, Felicity might find time for a less intense relationship. In the trailer above, she shares a liplock with someone. 

4. Russian Flashbacks — Season 5 is the last year of glimpses into Oliver’s past. As he becomes the Season 1 vigilante that viewers met in 2011, viewers will see how he joined the Bratva (the Russian mafia).

5. Lethal Force — The flashbacks aren’t the only throwback to Season 1. Oliver is also considering killing his enemies again, much to Thea’s (Willa Holland) dismay in the trailer above.

6. Villains —The Green Arrow will fight two big bads in Season 5. Tobias Church (Chad L. Coleman) is a criminal trying to unite all the dark forces in Star City. Prometheus is a little more mysterious. He is not a character from the comics, and the CW hasn’t even announced who the actor behind the mask is.

Arrow premiere date The true identity of Prometheus will stay hidden in the “Arrow” Season 5 premiere. Photo: CW

7. Diggle Returns — Dig (David Ramsey) will regret his decision to return to the Special Forces, and the experience will change him. “Things do not go according to plan for him,” executive producer Marc Guggenheim told Entertainment Weekly. “And there’s something that happens in the first three episodes that is fairly significant and it’s the circumstances that will ultimately bring him back to Star City, but he’s not going to be the same. He’s not going to be able to live his life the way he had been living it before.”

8. Mayoral Duties — Oliver has to be the mayor by day and the Green Arrow by night. Take a wild guess which job he blows off more often. While he is saving the world, Thea will discover that she is really good at her job as chief of staff.

9. Flashpoint — Though the CW/DC TV crossover won’t happen until midseason, the alternate universe created on “The Flash” will affect “Arrow” in small ways. Diggle and Felicity will feel the effects, but it still isn’t clear exactly what will be different for them.

“Arrow” Season 5 premieres Wednesday at 8 p.m. EDT on The CW.