So, in the interest of time, go read last week's Birds of Prey #21 post for the context of what's about to happen.
Mary leads Calvin to the Court's lab, where there be dead people Calvin can put in her costume, and fake her "death." Calvin thanks Mary for her actions, and urges her to fight the good fight, because he doesn't know just how good he'll be able to remain, as he leaves, and brings by Mary's "body" to Wycliffe, before being sent to find and kill Bane and his former mentor, Sebastian Clark.
Before Calvin leaves for Santa Prisca, he gets Wycliffe to allow him two minutes alone with Casey. He lets Casey her daughter is alive, at the very least, kisses her, and tells her to remember everything he's taught her. And off Calvin goes to Santa Prisca!
Calvin parachutes down to the island, avoiding the auto turrets which shoot down anything from above, and manages to infiltrate and disguise himself amongst Bane's ranks. Going through the prison Bane grew up in, Calvin passes by the Professor's lab where he sees all sorts of venom experiments going down.
Calvin gets spotted alone by a group of men, and to preserve his cover, follows them to a meeting with Bane, who is none too happy that the intruder's body wasn't found. How does Bane discipline the man who has failed him? By stomping his damn head in, because that's how Bane rolls. Sebastian is there too, and he ends up questioning the lengths of discipline Bane went to, which leads Bane to tell the rest of his men to escort Sebastian back to his quarters, because he's the boss.
This little escort gives Calvin a pretty good opportunity to blowdart the other guys, as he reveals himself to Sebastian, who is pretty surprised to see him.
Back in the Court's base, Casey manages to get one of her arms freed, and pulls out a fake tooth from her mouth, with a morse code transmitter in it. The code gets transmitted to Anya and Joey, who we met earlier in the series, who've apparently just been chilling on a beach, waiting for the call.
Back in Santa Prisca, Sebastian, although surprised to see Calvin, doesn't believe Calvin will actually kill him, because he's not a killer. Well, Calvin has other ideas, because now he knows just how much all the crap in his life is due to Sebastian, so he's willing to make an exception. Sebastian on the other hand has a few cards up his sleeve, one of which being one of the venom freaks Wolf-Spider, who comes to his aid.