Chapters 28-36 open with another condemnation of treacherous Ephraim, which had openly allied itself with the enemies of the sons of Yisrael. But Yeshaiyahu gives the odd prophecy that the people will be returned to the Law–little by little–by a foreign people. And the prophecy was realized. First, Hizkiyahu implemented his reforms and purged Yehudah of idolatry, then Yosiyahu was educated in Torah, then conquest and exile renewed ethnic sentiment and an interest in Torah, and finally, the Persians were impressed by the Jews and encouraged and funded the reestablishment of the Temple.
In the meantime, Hashem must plow before He can sow, and sow before He may reap. The reestablishment of righteousness and the annulment of the people’s “covenant with the grave” must take place. It will be painful, but the best things often are.
Hashem will strike Ariel, and reliance on Egypt will be foolhardy–as will retreat into the Negev and Egypt (Yeshaiyahu 29-31). But eventually a just king will reign over righteous princes, presumably Cyrus over his provincial governors (prophecies from the Persian period foretell not a king, but a prince/governor). First, though, less than a year from the time of the prophecy, Jerusalem will be conquered (Yeshaiyahu 32). Still, the conqueror (now Babylon) will ultimately be conquered, and all their chaos undone. Jerusalem will have the last laugh (Yeshaiyahu 33).
Babylon and Ephraim are not the only ones who will be destroyed, though; Edom will share their fate (chapter 34). As was the case with Babylon, Jerusalem and the other regions that have felt the wrath of Hashem will enjoy the final triumph.
Finally, chapter 36 reiterates the story told in 2 Melechim (2 Kings) of the emissary sent to frighten Yehudah into paying tribute to Assyria.