ABANDONED. YA/Fantasy - Girl is tasked with solving a crime? or mystery of someone using some sort of magic they are not allowed to have

[Jessica]

Right in the beginning, the girl arrives by horse, having ridden from an adjoining kingdom. There is a magic system (of sorts). People who have an affinity are tested at a young age and sent to the kingdom the protagonist comes from, using these powers are forbidden. But those who are tested and sent to the kingdom early are controlled? or just given rules and a job. I believe the king that summoned the girl is really ill, I can't remember if his summoning her has to do with his illness or with finding the lost girl (his daughter?).

Here's most of what I can remember.

Girl is summoned to kingdom to solve a mystery. She is tasked with finding the king's daughter?'s killer. Daughter was in love with a boy, the boy went missing, so did the girl. They suspect that the boy killed the girl. There is magic, some sort of water/air/earth control? The protagonist has a healing/water/air(whatever) power. She can heal plants(I think it was). Long search and asking questions, the boy who died? killed the daughter - his parents are mum about his whereabouts or what happened. There's a party, the protag and her bodyguard? have a connection (he is someone important I think, to the king). Once at this lavish party, there is this powder the royals drink called "golden dust", which apparently puts them on a trip. The protagonist and the bodyguard are drugged and they end up in the same bed (dunno what happens after this.)

Closer to the end, the girl goes to search another lead she had, the daughter had been tied up in a home (of a local that has many banana trees), she was killed, burned alive(I think). Protag goes to this house, is asked to heal the blight on the lands, refuses, is knocked out for a day or so, then is rescued by (someone?) not the bodyguard, he was also knocked out and tied up.

This is a bit all over the place, I apologise! I've been trying to figure this out for weeks! This is not a recent release, think I read it about 2-3 years ago.

[Elias]

I'm going to bump this, as it sounds great.

[Lobstergirl, au gratin]

Jessica, are you still looking for this or did you find it?

[Lobstergirl, au gratin]

No response, moving to Abandoned.