Epigonoi

The arc of the story of Thebes is not complete without the story of the Epigonoi, the sons of the first Seven who returned 10 years after the first attack (in which 6 of the 7 original Argive generals lost their lives) and succeeded in taking the city.

Thersander 1, son of Polynices and Argia 1 (daughter of Adrastus 1), was determined to sit on the throne he believed should have belonged to his father, by deposing his cousin Laodamas 2, son of Eteocles 1, now king of Thebes. The EPIGONI appointed as their commander in chief Alcmaeon 1, son of Amphiaraus and Eriphyle, following an oracle that predicted them victory under his leadership. This time they made sure that the army marching against Thebes would be strong enough. For that purpose, they added to their forces from Argos contingents from Messenia, Arcadia, Corinth, and Megara. More here.

Interestingly, a fragment of a play by Sophocles titled Epigonoi was found a few years ago, part of a cache that made for an exciting discovery announced in 2005:

Wisdom awakes: Sophocles' words are legible again. 

Speaker A: . . . gobbling the whole, sharpening the flashing iron. 

Speaker B: And the helmets are shaking their purple-dyed crests, and for the wearers of breast-plates the weavers are striking up the wise shuttle's songs, that wakes up those who are asleep. 

Speaker B: And he is glueing together the chariot's rail. 

These words were written by the Greek dramatist Sophocles, and are the only known fragment we have of his lost play Epigonoi (literally 'The Progeny'), the story of the siege of Thebes. Until last week's hi-tech analysis of ancient scripts at Oxford University, no one knew of their existence, and this is the first time they have been published.

Other accounts of the war of the Epigoni were produced by Pseudo-Apollodorus and Pausanias.

Indeed, the arc of the tale of Thebes was quite an arc. An earlier epic about the Epigonoi is lost, which was part of the four-epic Theban Cycle. Shameless crib from Wikipedia:

The epics of the Theban Cycle were as follows: 

The Oedipodea, attributed to Cinaethon: told the story of Oedipus' solution to the Sphinx's riddle, and presumably of his incestuous marriage to his mother Epicaste or Jocasta. 

The Thebaid, of uncertain authorship but sometimes attributed in antiquity to Homer: told the story of the war between Oedipus' two sons Eteocles and Polynices, and of Polynices' unsuccessful expedition against the city of Thebes with six other commanders (the "Seven Against Thebes"), in which both Eteocles and Polynices were killed. 

The Epigoni, attributed in antiquity to either Antimachus of Teos or Homer: a continuation of the Thebaid, which told the story of the next generation of heroes who attacked Thebes, this time successfully. 

The Alcmeonis, of unknown authorship: told the story of Alcmaeon's murder of his mother Eriphyle for having arranged the death of his father Amphiaraus (told in the Thebaid).

For our purposes, it is worth noting that the role of a woman, Antigone, is pivotal in the overall plot.