It starts with Tsukina making a giant barrier that heal and protect the people. Ill who's next to her see the savior crest lit up on the back of her head (the location is basically on her scalp, so the only way anyone would've been able to find it would be to shave her head :v )
And God recovered the other savior girl, who seem to have lethal wound on her stomach.
Ill then ask if Tsukina is another Savior.
She apologize for deceiving him then teleport away to her cafe.
Once there, she felt light headed from using up too much magic, though she expects the barrier to last for decades given the amount of MP she used.
Then as she think about how the next time Ill appear, it'll be in his capacity as the castle's messenger rather than just to visit her, she fell asleep.
Next morning, she's still tired, and thinking that nobody would be coming anymore, she was going to keep sleeping.
Until she heard Ill's voice.
She look up to see Ill holding a bouquet of flower.
He gave it to her, and propose to her on the spot. (well, 'I like you. I'd like you to go out with me with assumption of eventual marriage' or something like that)
Tsukina was surprised.
Ill then ponder how he didn't realize it earlier, considering Tsukina's massive magic power and how she didn't know of a festival that every child would know about.
Tsukina was about to say something about if he's doing this to gain her cooperation (i.e. just trying to gain her favor)
He immediately shot that down with a serious look, not to mention right now there's no need for it, and also he won't tell anyone about her being a Savior.
He then proceed to explain how the country IS searching for her.
He explains that the barrier she put up cover the whole country, constantly healing any allies and preventing any attacks from the outside.
Given the scale and strength of it, everyone's certain it must be the work of another Savior and are searching for the person.
And also, if one is capable, this country allow for multiple spouses (whether a woman with multiple husbands or a man with multiple wives), so given her power there's definitely going to be proposals from other countries or major merchants.
And he absolutely don't want that, he want her for himself, and that's why he's going to keep quiet about her.
Tsukina "...you're fine with me?"
Ill "Tsukina is fine (too)"
She said yes, then the headache from lack of MP came back, and he told her to sleep, he finally got a day off and will be here when she wakes up, after all her barrier have ensured peace in this country for decades to come.
After that the epilogue is just Tsukina's monologue.
How Ill kept quiet everything about her.
How the prince sought to be punished, but since there was no casualty in whatever that other savior girl did, his sentence was just being under house arrest in the depth of the castle for some years.
And how she's officially engaged to Ill.
How she asked Ill to let her go greet his parents (said parents were in tears since they've given up on Ill ever getting a girl)
How Ill move to her shop and commute to the castle from there.
And how while this country has the barrier, the monsters still exist outside, and there's the Demon Lord too.
Even so, she's got her hands full just protecting her current happiness here.
So she'll just leave the task of world peace to some other young savior in the future....
And the last page seem to suggest this 'arc' is over, but there'll be continuation under different (slightly?) title starting this Winter.
So kinda like Bookworm's arc 1/2/3 being under different title (and artists) I guess.