The Middlemist Field is a field located in Camelot and is the only known place where the Middlemist flowers blossom. Centuries ago, a man named Vortigan nearly caused the flowers' extinction after destroying them, but Nimue managed to salvage a few seeds which Merlin allowed to grow with his magic. Many years later, the flowers became a beloved part of Camelot and also Guinevere's favorite flower.
Before the Curse
Merlin uses magic to help the Middlemist flourish. ("Nimue")
A masked man named Vortigan burns Nimue's village to the ground, killing her friends and family and leaving her with nothing but a handful of middlemist seeds that she managed to escape with, bringing them to the great Sorcerer Merlin so that he may begin growing the flowers anew because she believes that her best revenge would be to let the flowers prosper in spite of the man who burned them away. He speeds up the process with his magic, intrigued by Nimue because he cannot see her future, and the two of them soon enter a relationship. He wants to propose but is fearful because he is immortal and she isn't, meaning her would leave her behind. Nimue eventually drinks from the Holy Grail, but uses her magic to kill the man who destroyed her village and family. Afterwards, the rescued middlemist go on to blossom into a giant field over many, many years. ("Nimue")
Before the Third Curse
Emma saves her lover's life in the Middlemist field. ("Birth")
When Emma absorbs the darkness and becomes the new Dark One, she begins getting visions of Rumplestiltskin in her head that only she can see. The visions and temptations become too much for her and she has a minor meltdown. To help her get her mind off the visions, Hook takes her on a horse ride to the Middlemist field. Once there, Emma realise she's free of the visions and goes on to embrace in a kiss with her lover. ("The Broken Kingdom") When Hook becomes mortally wounded by Excalibur, Emma, desperate to save his life, teleports him to the Middlemist field where she extracts Merlin's powers and puts them inside Hook. However, this action goes on to make him into a second Dark One. ("Birth") While looking for Hook, Emma heads to the Middlemist field where she rescued him, and when there's no sign of him, she uses Excalibur to summon him. The two talk and seem to make amends...but it doesn't last for long and he ends up betraying her. ("Broken Heart")