An old lady lies on her deathbed, and can't shake the nagging feeling that she's had an empty life. (This is why she is dressed in white.) She tells herself that there is only one correct "path" to take in life, and that she has taken it. But she can't quite convince herself. So she imagines how she could have been a different person, a more interesting person, when she was younger. The game takes place inside her mind.
Each of these possibilities appears in the game as a girl. One is enthusiastic about animals. One is enthusiastic about art. One is enthusiastic about exploring. One is enthusiastic about men. And so on. The old lady who never got too close to anything imagines herself as a pure little kid dressed in white, and watches these red-clothed girls try to do better than she did. She occasionally pushes them along, either to go to the straight path or to get to the ultimate realization of their enthusiasm.
The purpose of this mental exercise is for the old lady to reassure herself that personality is bad. The girls' clothes are red, which in my opinion represents only death. If this dying woman can prove to herself that the path she took is better than any other, than (she hopes) she can be comfortable with death. So the white girl puts on an air of objectivity, pretending she does not care which way the girls go, but really what she wants is to see them all die in worse ways than herself.
If a red girl follows the path, she gets exactly where the old lady got: to the boring house where she sits in her bed. This is unsatisfying and the woman considers it a "failure", because she has proven nothing. Whatever girl made it there continues to hang around in the house, continuing the nagging sense that there could have been a better life.
But if she leaves the safe path and finds the place reflective of her own personality, the old lady wins, because then she can imagine gruesome ends for each of these girls. So the animal-lover is eaten by a werewolf, and the explorer drowns in a big lake, and the man-chaser gets chopped up by a madman with an axe. And the white woman can take comfort in her own blandness, because it couldn't have ended in that horror.* "Success"! That girl leaves her alone, leaving only a few other possibilities to weigh on her shoulders.
So one by one, the lady puts her imaginary selves into the forest, and enjoys seeing them mutilated and tortured. Finally she is rid of all of them, and there is no one left in the house but herself. So the white girl walks through the forest, seeing all the places and not bothering to interact with any of them. There's a red tent, which she can enter and exit at will. "Ha!", she says, "I can pretend to have personality too, but because it's not real I can get out of it again untarnished! But look at you! You took yourselves too seriously, and ended up living short, hellish lives!". The forest is quite boring without anything to do in it. Finally she goes back to her house, as plain as ever, and looks back at where she's ended up. There she is in that bed, in the moments before her death, and next to her bed she imagines a wolf waiting to devour her, which might never have actually been there.
Then she realizes where she is. She has never taken any risks and still she is dying! In her house, the white girl finds her dress covered in red. In death she is just the same as the others! And so the red girls, who she thought herself rid of, come back in one by one, and her self-image of purity leaves.