- We're at Barabas's place, and he's ordering a bunch of carpenters to build some sort of complicated pulley-rope-crane device.
- After they've finished and left, Ferneze comes in, carrying a big sack of money he's put together from the Maltese citizens.
- Like, really really big—100,000 pounds, in fact.
- Barabas dishes on the plan:
- There are cannons hidden beneath the monastery where Calymath's army is feasting, and at Barabas's signal the entire thing is going to blow up.
- The floor of Barabas's house, where Calymath himself is going to be eating, is rigged so that when a cable is cut it drops down into a pit.
- This last bit is Ferneze's job—he has to cut the cable at the right time.
- Ferneze hides, and Barabas crows to himself about how very clever his plan is.
- Calymath comes in, but before Barabas can do much Ferneze bursts out, telling Calymath that he's going to do better by him than Barabas would have.
- Things are already set in motion, though—a Knight gives the signal to blow up the monastery, and the cable is cut.
- It's Barabas, though, not Calymath and his bashaws, who falls through the trap door, and into a cauldron which has been placed below.
- It would appear that Maltese cauldrons are sold in the sizes of Small, Medium, Large and Extremely Nasty Death For Adult Men.
- As Barabas cries for help, Ferneze explains to Calymath that the trap was devised by Barabas and meant for Calymath.
- Once Ferneze makes it clear he's not going to help Barabas, Barabas figures now's as good a time as ever to confess to killing his son.
- While he's at it, he tells Calymath he wants to kill him too—in fact, he wants to destroy all the Christians and Turks.
- The cauldron is on fire, presumably (we don't actually get a stage direction for this, but Barabas complains of "the extremity of heat," so why not?), and having cursed both Christians and Turks alike, Barabas finally dies. For real, this time.
- Ferneze, repeating that he's done Calymath a big favor by not killing him, tells Calymath that he has to stay in Malta—after all, all of his Turkish men are dead.
- Say what? Yep, that's right. That sound you heard? Exploding monastery. Sorry, bros.
- Ferneze's going to hold Calymath hostage in Malta until his father, the Emperor of Turkey, makes reparations and frees Malta.
- Ferneze closes the play by swearing he won't let Calymath go until his demands are met, and thanking heaven for his victory.
- And that's a wrap.