Grant Gustin does the voiceover at the beginning. After all, he's the Green Arrow!

Diggle is fighting Deathstroke's son. He doesn't stand a chance. But when the three heroes show up, Diggle is like, oh, man! When the three of them show up, he knows they have a huge problem.

Barry doesn't know things are "fraught" between Oliver and Felicity. 

The three head to Gotham and find themselves on top of a building with the Bat signal. They don't use it because duh.

When they get mobbed in an alley, Barry is recognized as Oliver Queen and the trio are arrested. They're bailed out by Kate Kane. 

They meet Kane and chat about Batman and his disappearance from Gotham three years ago. 

In Star City, Felicity is shocked that Iris knew something was up with Barry but she didn't follow suit.

Kate and Kara chat. Kate shares that she's Bruce Wayne's cousin. Kara notes her cousin has some notoriety, too.

Kate is a very determined chick. Her walk toward her Batwoman costume is odd.

Oliver and Diggle head to the asylum to chat with John Deegan. 

To escape from the gang, Deegan sets the inmates free. Oliver tells Diggle to get the inmates back in their cages and find that book!

Caitlin runs into someone who freezes her. 

The Flash puts all the inmates back in their cages.

Supergirl can't find Deegan or the book.

A black van slams into Cisco and tosses his ass into the air. Batwoman lands on it and she's much cooler in costume.

Killer Frost is being all frosty. 

Deegan finds his book, but Supergirl get it. Deegan gets away, though.

In a warehouse, a case of Crank spills and Barry screams for Oliver. Malcolm Merlyn steps forward to tell Barry Oliver isn't there and nobody is coming to save him. Eobard Thawne in the form of Wells steps forward saying the same.

Oliver and Barry are fighting each other because they think they're each other's worst enemies.

Kara says goodbye to Kate Kane who is only too happy for them to get the hell out of Gotham.

After Oliver makes amends with Felicity, a portal opens and a flash steps in. It's not Jay Garrick but looks like him. He's Barry Allen from another earth. He knows Diggle, who should have a ring. He's from Earth 90, as we saw at the beginning of The Flash.

The who gave Deegan The Book of Destiny is testing everyone about a crisis. 

Dude changes things again. Trigger twins are wanted and Diaz is a cop. Superman has gone bad.