PROLOGUE
A forest, once upon a time.

Deciding that life is too much to bear, a scorned young woman kills herself by drowning in a woodland lake.  Upon her death, she transforms into a water spirit.

ACT I
The same forest, after time has passed.

A trio of Wood Sprites call out to Vodník, a water gnome, teasing him.  Rusalka, now a water spirit, appears.  She tells Vodník that she has fallen in love with a human – a Prince who comes to swim in her lake.  Now she wants to become human herself to be with him.  Vodník is horrified and tells her that humans are evil and full of sin – Rusalka counters that they are full of love.  He reluctantly tells her to get help from the witch Ježibaba.  Rusalka calls on the moon to tell the Prince of her love.

Ježibaba agrees to turn Rusalka into a human, but warns her that if she doesn’t find love, she will be damned – and the Prince will die.  Further, in becoming mortal, she will lose her power of speech. Convinced that her feelings for the Prince can overcome all spells, Rusalka agrees and Ježibaba gives her a potion to drink.

As dawn breaks, the Prince appears with a hunting party and finds Rusalka by the lake.  Even though she won’t speak to him, he is captivated by her beauty and leads her away to his castle.  From the lake, the voices of Vodník and the water nymphs are heard, mourning the loss of Rusalka.

~ intermission ~

ACT II
The Prince’s castle, a week later.

As his castle busily prepares for a ball, the Prince wonders why Rusalka is so cold toward him, but remains determined to win her.  A Foreign Princess, who has arrived expecting to become engaged to the Prince, reproaches him for ignoring her.  The Prince, embarrassed, turns on Rusalka and escorts the Princess into the evening’s festivities.

Vodník appears outside the castle, lamenting Rusalka’s fate.  Rusalka suddenly rushes out in tears.  She begs Vodník to help her, telling him that the Prince no longer loves her.  The Prince and the Foreign Princess come into the garden, and the Prince confesses his love for her.  Rusalka overhears and rushes into his arms, but he rejects her.  Vodník curses the Prince, then disappears with Rusalka.  The Prince asks the Foreign Princess for help, but she tells him to follow Rusalka into hell.

~ intermission ~

ACT III
The forest.

Rusalka waits by the lake, lamenting her fate.  Ježibaba mocks her, then hands her a knife and explains that there is a way to save herself: she must kill the Prince.  Rusalka refuses, throwing the weapon away.  When her sisters reject her, she sinks into the lake in despair.  The Wood Sprites try to tease Vodník again, but he tells them what happened to Rusalka, and they fall silent.

The Prince, half-crazy with remorse, emerges from the forest, looking for Rusalka.  She appears from the water, reproaching him for his infidelity, and explains that now a kiss from her would kill him.  Accepting his fate, he asks her to kiss him to give him peace.  She does, and he dies in her arms.  Rusalka asks for mercy on his soul and disappears into the water.