Cicero runs into Casca on the street that night. Casca's a little shaken up. Though he's seen his fair share of bad nights, he says the sky is dropping hot fire is definitely a first. Casca thinks maybe there's a civil war in heaven, or maybe the gods are raining down fury because the world has displeased them.
This would all be crazy talk except that Casca's seen worse than bad weather tonight. A slave boy's hand was lit on fire by a torch, and yet it didn't burn. Then there was a surly lion at the Capitol. Also a bunch of women were terrified by a vision they swore they saw of men walking the streets covered in flames. Casca reports the strangest thing of all: a nighttime bird was in the market, during the daytime! Since it doesn't get any crazier than that, it's clear all these things are bad omens. (Seriously, a nighttime bird.)
Cicero thinks they should hold off on crazy interpretations of the flaming men, lions, and various insomniac birds. He says people basically interpret things to mean whatever they want them to mean.
After confirming that Caesar will be at the Capitol tomorrow, Cicero leaves.
Casca then runs into Cassius, who has been presenting himself to the heavens to be struck by lightning. A tad concerned by this behavior, Casca asks Cassius if maybe he should have trembled at the gods' warning instead of going out for a lightning tan.
Cassius thinks Casca is an idiot. Obviously the heavens are making the world disco-fabulous to signal their serious displeasure with the state of affairs in Rome, where a certain someone, though he is no better than Cassius, has grown too powerful for his own good.
Casca, dumb as socks, asks whether Cassius is talking about Julius Caesar. A true politician, Cassius does the old "maybe, maybe not."
Either way, Casca says the Romans are acting like cowards by doing nothing to stop the tyranny, which will only get worse. Casca has heard that tomorrow the senators will crown Caesar king, and that he plans to wear his crown everywhere but Italy.
Cassius points out where he'll wear his dagger, and basically blabs his plan to murder Caesar.
The thunder stops (drama!), and Cassius contends that Caesar is only a tyrant because people are stupid and beg to be taken advantage of.
Cassius pretends to be surprised about revealing so much in front of Casca, who he suggests might like being Caesar's stupid stooge.
Casca takes the bait and pledges not to tattle. More important, he pledges to join in on the conspiracy to kill Caesar. Conveniently, there's a meeting of all the conspirators starting right now at the old theater, Pompey's Porch. They're waiting for Cassius.
Cinna, another conspirator, happens to be on his way to that same secret meeting, and they all stop for a chat. Cinna mentions it would be really nice if Brutus was also interested in killing his friend, Caesar.
To further this goal, Cassius sends Cinna on an errand to plant some letters Cassius has written in various places where Brutus will find them. Cassius has impersonated other Romans in the letters, all of which praise Brutus and suggest that somebody should really off Caesar for Rome's sake.
Cassius confides to Casca that they'll have Brutus on their side in no time. Casca is glad, as Brutus is well regarded and will make all the nasty things they do seem virtuous and worthy.
Cassius agrees they really do need Brutus, and by morning they'll have confirmation on whether or not he'll join them.