Pericles is back in Tyre, overwhelmed by melancholy. In a monologue, he reveals that his mind is occupied with worry about the dangers of Antioch; he is convinced that Antiochus will not be content to see that Pericles has remained silent, and will probably take action against him. He imagines Antiochus will invade Tyre, threatening a war that Pericles is sure his people will lose. Several lords enter with Helicanus, one of Pericles's counselors. Helicanus scolds Pericles for languishing in his gloom, and offers his advice. Pericles sends the lords away and listens as Helicanus suggests that Pericles bear his grief with patience.
Pericles tells Helicanus about his trip to Antioch, his discovery that Antiochus and Antiochus's daughter are engaged in incest, his flight, and his worry that Antiochus's tyrannical nature and fears will lead him to invade Tyre. Pericles has been trying to think of ways to "stop this tempest ere it came" (I.ii.103). Helicanus says he understands Pericles's fear of either a public war or a private treason, and urges Pericles to travel away from Tyre until Antiochus's anger is past, passing the throne temporarily to Helicanus himself. Pericles agrees, and decides to depart for Tarsus, believing Helicanus is a trustworthy advisor.
Meanwhile, Thaliart enters Tyre, intending to kill Pericles, though he will be hanged in Tyre for it. He reasons, simply, that if he doesn't commit the crime he will be hanged at home. Helicanus and Aeschines, Pericles's other advisor, enter with some lords. Thaliart overhears them talking about how the king has departed. Thaliart introduces himself to the court, saying he has come with a message from Antiochus for Pericles, but will have to take it back to Antioch since Pericles is gone. Thaliart determines to tell Antiochus that Pericles perished in the sea.
A melancholy protagonist recurs in Shakespeare's dramas and comedies. But in this case it seems almost as if Pericles feels he should be melancholy merely because he is the main character. Often melancholy characters bemoan their love life, as Romeo does, or worry themselves about some political unrest, like Hamlet's obsession about his father's death or Brutus's alarm about the nature of Julius Caesar's leadership. Yet Pericles is not in love, and there seems to be no political unrest in his kingdom. Why, then, the melancholy? Is it merely that he fears Antiochus will have him killed or unjustly attack his nation? And if so, would fleeing Tyre place him out of danger? Probably not. The melancholy nature of Pericles in this scene seems like a stock gesture, making him a recognizable hero to an audience used to melancholy leads, but without making his situation actually very deserving of such a response.
Helicanus here begins his run as Pericles's loyal second-in-command. He suggests Pericles leave Tyre and offers to care for the kingdom, not because he has ambition to the throne, though many in his position could well have benefited from Pericles's departure. Figures of charity and loyalty appear throughout the play, as contrasts to figures of evil and cruelty.
Thaliart isn't the most bloodthirsty of assassins, since his main concern is whether he will be killed for carrying out, or not carrying out, his orders. His decision to lie about the death of Pericles to Antiochus is the first of many untruths, told by assassins and others, about the death of a major character.