Post-Troy au where Diomedes visits Mycenae on the regular in secret because he misses Argos and Mycenae is close enough & is the next best thing available. It is there that he meets a girl (Perseid by the looks of it, but there are many such descendants born of bastard lines, so he pays little mind to it) at the marketplace, haggling over something inconsequential.
He doesn't know why but he pays it for her, and is promptly surprised by her glare and sharp words, as she all but spits out that she is no beggar to accept charity. She is less protesting of his aid when he helps her from being knocked over by a moving cart and its cattle. So starts a strange friendship.
Whenever he feels homesick or Italy gets too much, he takes a ship to Corinth, and a chariot to Mycenae afterwards. He doesn't dare announce his presence, nor does he visit the halls of Agamemnon, which now belong to his murderous wife. Instead, he spends his time with her.
She doesn't give him her name and he doesn't give him hers, but they talk for hours on. From her stories, it is likely that she is the daughter of some well off man who was killed alongside Agamemnon (it is strange to think he would have seen or even known her father). There is something about her appearance and her manner of speech that is familiar, but for once his mind is unable to make the connection.
Soon it becomes less about Argos and more about her. Visiting her, spending time with her, walking the markets, sharing a meal, hearing her sorrows, her yearning for her dead father and her upset with her mother & her step-father. It is improper for a woman to be spending so much time alone with a strange man, but she pays no heed to such concerns. The sorrows she shares are much alike to his - a dead father, an estranged mother - he understands her and she understands him like no one else.
The affections that he had thought dead after Aegiale's betrayal return back with full force, twice as strong. He enjoys the rare smiles that bloom on her beautiful face, how her calloused hands fit in his, how her green eyes shine like olives in the sun. Love, he thinks when he sees her sleeping away on his shoulder, her face relaxed in sleep as it has never been awake. Love, even though he is the son of a royal line and she is but a commoner.
It is only when he returns after a long time spent away from Mycenae due to his duties in Italy, does he find out about the turmoil in Mycenae, about Helen and Menelaus' return and Orestes' grave crime. And then he finds out she is none other than the Princess Elektra, eldest living daughter of Agamemnon.
