Minthara is a potential companion that you can recruit in Baldur's Gate 3. If Minthara is imprisoned in the Moonrise Towers, this is your only chance to save and recruit her while it's still possible. How to do this, we will tell in this guide.
To reach this point in Baldur's Gate 3, you must side with Minthara by destroying the Emerald Grove (or side with her without destroying the grove). There is another option where you kill three leaders in the Goblin Camp as part of the Emerald Grove quest (one of whom is Minthara), but the final blow to Minthara must be non-lethal — this way she will lose consciousness and remain alive.
After siding with Minthara, convince her to meet at the Moonrise Towers. However, upon entering the throne room there, you will see that Minthara has somehow angered Ketheric Thorm. Eventually, during this scene, you will be given various dialogue options that use a Wisdom check, but all these options will lead to the same outcome: Minthara will be sent to the prison located beneath the towers.
After this scene, you will receive the quest Resolve Minthara's Fate. This will activate a quest marker that will show where the staircase to the Moonrise Towers prison is, and it is there that we can save Minthara from execution. If you still can't find her, just go through the west exit from the throne room up a small staircase, then go down the next staircase right in front of you. Once in the prison, head to the southern part of the area to find the prisoner.
The first way to deal with this unpleasant situation is to convince the guards to let you deal with Minthara. Once you start talking to them, choose the first dialogue option. After this, you will be given options for a Deception or Intimidation check. Choose the one in which your character is more proficient to proceed further.
This will allow you to either attack the guards immediately or delve into Minthara's mind. If you manage to pass the check with a difficulty of 18, you will be able to talk to Minthara through her consciousness.
Here you have three options:
For our purposes, either of the first two options will do. If you decide to make her simulate obedience, you will need to pass a Intimidation, Deception, or Persuasion check to convince the guards that the job is done.
Once Minthara is freed, you will need to get her out of the Moonrise Towers. As soon as you exit the prison cell, one of the nearby guards will stop and ask you to explain what's going on. Again, you will need to pass a Intimidation, Deception, or Persuasion check. Otherwise, you will have to fight the guards at the cell. It doesn't matter what the outcome of this conversation is, because you will still have to fight your way out afterward.
Then head straight through the front door of the location. Here, there will be one final conversation before Minthara is truly free.
We recommend keeping in mind that depending on your playthrough, there may be other prisoners in the jail: tieflings, the dwarf Wulbren, or all of them together.