"Arrow" characters Oliver Queen (Stephen Amell) and Barry Allen (Grant Gustin), joined forces in the second crossover event with "The Flash." CW

In the shocking second half of the crossover event between “Arrow” and “The Flash,” things take a very confusing turn as the battle to take down a mysterious new villain heats up. In addition, the hero of Star City learns that he’s got another family member to take care of.

Before reading any further, it’s worth checking out the first half of this story that took place on the Tuesday, Nov. 30 episode of “The Flash” Season 2. However, if you’re only interested in the Green Arrow’s half of the story, here’s what happened:

The episode opens with the team relocating to a safe house Oliver (Stephen Amell) had set up in a remote location outside Central City. The idea is to hide their new friend, Kendra (Ciara Renée), who was revealed during “The Flash” to be the next reincarnate of Hawkgirl, away from the assassin trying to kill her. However, that’s just step one of the plan given that the person trying to kill her is an immortal, knife-throwing mystic who has a sense of where Hawkgirl, and her paramore Hawkman (Falk Hentschel), are at all times. It’s a two-team effort to take down Vandal Savage (Casper Crump) as the team takes the fight to “The Flash’s” home turf.

However, despite being a solid tactical move under the circumstances, Oliver has another motivation for returning to Central City. Those that watched this week’s episode of “The Flash” to the end will remember it finished on a cliffhanger involving Samantha Clayton (Anna Hopkins). For those that don’t remember, Hopkins was a former flame of Oliver, before he ditched his bad-boy persona and became the Green Arrow. He got her pregnant during their time together ten years ago. It was revealed that Oliver’s mother had paid her off to tell him that she had a miscarriage. All was well for Queen, until he was bumped into by Clayton’s 9-year-old son on “The Flash.” Although defeating Savage is still their number on goal, Oliver visits his ex. She keeps her word to his mother and says the boy isn’t his. Unfortunately, thanks to some forensic help from an unknowing Barry Allen (Grant Gustin), he discovers she was lying.

Meanwhile, now that Malcolm Merlyn (John Barrowman) and his League of Shadows, are back in town, he calls a meeting with himself, the Green Arrow, Flash, and Savage. It’s not often that someone in Merlyn’s position encounters a person he doesn’t know with abilities he’s never seen before. As a result, he’s terrified, especially since his daughter, Thea (Willa Holland) is involved. They go to the meeting in a dark, abandoned warehouse and Savage gives them 24 hours to turn the Hawks over to him or he’ll brutally kill everyone on both Team Arrow and Team Flash.

Merlyn isn’t playing around, he wants Oliver to give Kendra up and end this whole mess. He obviously refuses and immediately gets to work on a plan. While that’s happening, Barry reveals to Cisco (Carlos Valdes) that he “ghosted” while running to the meeting the night before. As fans of “The Flash” will know, this kind of thing is indicative of the time-travel that they tend to deal with in Central City. Fearing disrupting something in the natural timeline, they choose to ignore it and get on with the mission. The plan, to take down Savage gets a big help from Team Arrow, which discovers a video tape a professor made regarding the immortal. Like the Hawks, he is an Egyptian with mystical powers. The powers resulted from an “earthly calamity” and only an object closely related to that calamity can harm him. Kendra suggests using the staff that the villain acquired during the previous episode. The hope is to pretend to turn over the Hawks and then surprise Savage at the meet. Withs some specially developed gauntlets, Flash should be able to grab the artifact right out of his hands.

Before they hatch the daring plan, Oliver confronts Clayton about his son. She admits to lying about him being the father at his mother’s request, but reveals she never cashed the check. She claims she didn’t want him to end up like his dad, who she thought was a drunken billionaire playboy. Although she admitted he’d turned his public persona around, she still feels there’s a risk to letting the boy get caught in Queen’s orbit, with no idea who right she is. She says that he can never tell anyone, including Felicity (Emily Bett Rickards), that he knows about the kid. If he does, she won’t ever allow him to see him. Oliver agrees, but the secret-keeping doesn’t last. Felicity found the DNA test that Barry did for him and she’s furious. She says that after all this time, if he couldn’t trust her with this information, then he’s never going to trust her. Barry steps outside just in time to see them break up.

Oliver goes into battle with his head really not in the game. He only brings himself, Flash and the Hawks, for fear of what Malcolm would do if Thea got hurt. When the group launch their attack, Barry quickly gets hit by Savage before he can grab hold of his magical staff. Hawkman had been teaching Hawkgirl some tricks to remember who she is and access her warrior priestess nature, but they don’t work when the time comes. Savage quickly kills them both. Barry eventually gets the staff, but it’s too late, Savage overpowers them. The blast from the confrontation emits a wave of energy that burns Oliver down to a skeleton. The Flash runs as it engulfs the city, killing everyone in its path. He hits top speed trying to avoid it and starts to ghost again. Before he knows it, he finds himself in a dark, abandoned warehouse one day prior, about to meet with Vandal Savage.

With the clock essentially reset on the group’s 24 hour ultimatum to stop Savage, Barry decides to help. He reveals to Oliver that the plan they come up with doesn’t work. After some convincing, he tells Oliver that the plan to grab the staff has to be rethought and that his head wasn’t in the game thanks to his actions with Felicity. First, they get to work on the gauntlets not working. He convinces Cisco to go talk to Kendra instead of Hawkman. In doing so, she remembers the root of their curse. Back in ancient Egypt, the Hawks initially found they were in love with each other. However, Savage wanted Kendra for himself. When he walked in on them together, he kills them both as a meteor crashes into the city. With full knowledge of the calamity in question, the Flash’s technology is able to grab the staff more accurately.

When it’s finally time to ride into battle, Felicity hasn’t discovered the DNA sample regarding Oliver’s son (although he knows he’s the father still), so they never break up. When the time comes to bring the suit up for the fight, a full-thinking Oliver gets the whole team involved this time. They attack again, this time with the full might of Hawkgirl. Despite their combined efforts, it’s still a pretty close bout. It, once again, comes down to just Barry, Oliver, Savage and the tug of war over the staff. However, given that this timeline’s version of Oliver didn’t have the weight of losing the love of his life on his shoulders, the power duo easily defeated their enemy.

From there, Hawkgirl bids a bittersweet farewell to Cisco, letting him down gently from their previous relationship. After all, who can argue with thousands of years of fate? Meanwhile, Malcolm Merlyn returns to the battle site to collect the ashes of Savage on behalf of the League of Shadows. With the bad guy put down, for now, and everyone’s respective relationships in good condition, the second crossover between “The Flash” and “Arrow” was complete.