The Calypso sequence in BOTL is very good.
For the romance, yes - I do think it is frankly astonishing that Percy and Calypso manage to be such a memorable couple despite interacting for (legitimately, no joke) one SINGULAR chapter out of a five-book narrative. And the sequence works well when it comes to further complicating Percy and Annabeth's relationship at the very worst possible time (although the Rachel-quest plot would have been plenty. It still adds to the nuance and the drama of it all in a way that did rewire my adolescent brain chemistry).
But Percy's encounter with Calypso truly does permanently change him - and it's because what she offers him is safety and avoidance. Both of which Percy desperately wants.
I think it is obvious that Percy is captivated and does fall for Calypso as a person. But it's impossible to divorce her from her island - and that's kind of the whole point of the whole sequence, isn't it?
The chapter is literally titled "I Take A Permanent Vacation." Ironic, funny, but also very poignant to frame it this way. Percy is literally burning to death and hurtling towards the earth like a comet the chapter before, he's so injured he can't stand up for more than a couple minutes at a time, he's comatose for like half the time he's even on the island. Nothing about this is anyone's idea of a dream vacation. But for the first time in his entire experience in the mythological world, he's in a beautiful paradise that truly is a beautiful paradise - not a trap or a gimmick. The protection is real. And the company is good. And so in that regard it very much does read like a vacation from his daily struggle of world-ending stakes and constant danger. He's offered the chance to have this forever.
What's beautiful about this offer is that it truly comes with no strings attached. He can stay as long as he wants and leave whenever he wants. It's the most convenient, most pleasant path to immortality you could ever imagine. He doesn't have to sacrifice his humanity to achieve it.
When Calypso makes her offer, she specifically contextualizes it in terms of avoiding the war and the prophecy. Two things which the reader already knows: Percy does NOT want to face.
"You would never age or die. You could leave the fight to others, Percy Jackson. You could escape your prophecy.β
And the reason it works so well is because he really, really does want this:
I stared at the horizon. The first red streaks of dawn were lightening the sky. I could stay here forever, disappear from the earth. I could live with Calypso, with invisible servants tending to my every need. We could grow flowers in the garden and talk to songbirds and walk on the beach under perfect blue skies. No war. No prophecy. No more taking sides.
It's an offer for literal escapism. To a kid whose identity is partially formed around the concept of never feeling safe - even more than that, to a kid whose very existence is perceived as such a threat that the gods have discussed killing him to minimize collateral damage. And he has just had to come to terms with the fact that he is dangerous and he really can cause very severe damage to the world.
The thing about this offer is that it's not even real, it's an illusion - should Percy actually do this, there's no reason to believe that Kronos' conquest would not touch Ogygia. She's the daughter of Atlas, imprisoned for fighting on Kronos' side in the first war. She's probably getting broken out, at least at some point, even if it takes them a few hudred years or so to get around to it - or perhaps the magic of Ogygia (enforced by the gods, at least in PJO canon) would simply stop binding Calypso once Olympus is overthrown. Regardless, it doesn't matter - because Percy's decision is not about reality. It's actually the opposite. When faced with a chance to avoid his fate without anyone knowing - Hephaestus has explicitly said that he didn't tell any of Percy's friends that he's alive because he wasn't sure if he was coming back! - what will he do? Is he in this war by choice, or because he has no other option? It's a reinforcement of his decision to claim the prophecy to protect Nico from it at the end of TTC, but I would argue that it's stronger, because nobody is watching him in this moment but Calypso, who wants him to stay. There's nothing to be gained for Percy by leaving - nobody is going to know how selfless this decision is. He doesn't get credit for this moment of heroism. It's not showy. And he chooses to keep it private after he returns.
This decision also comes on the heels of Calypso and Percy's conversation about why she fought for Kronos in the first war. Percy's worldview has been challenged before, but really only by Luke, the antagonist. But this is coming from someone Percy likes, admires, associates with goodness. And she asks him a question that Percy will struggle to answer: "do you support the gods because they are good, or because they are your family?β
This question is going to be a really, really important one in the next book, and this moment sets up for that perfectly.
It's really no wonder that he specifically asked the gods to set her free as part of his wish. It's also no wonder that he leaves this encounter feeling like she'll always be his biggest "what if." Yes - romantic, sure. But it was much more than that. And it did change him.
