"Rage and magic could not wake them, but the terrified screams of their daughters broke the curse Gormlaith had laid upon them, which, like Gormlaith herself, took no account of the power of love."
-- J.K. Rowling on "Ilvermorny School" (Pm)
When Gormlaith Gaunt attacked Ilvermorny School, she sent a powerful curse towards the building, including the names of her niece Isolt and her husband James Steward who were both sleeping (Pm). When the twin baby daughters of Isolt and James woke up and started to cry in fear, the sound broke through the Enchanted Slumber due to the power of love, which Gormlaith did not understand (Pm).
References from the canon
- Since Gormlaith did not know about the four children living under the same roof, she did not curse them by including their names (Pm).
- When Gormlaith also put Isolt's wand to sleep, the Parseltongue word for "wand sleep" awakened the twin River Serpent cores in the Boot brothers' wands, which emitted a low musical note alerting them to danger so they could fight off Gormlaith (Pm).
One could say that Love is the Countercurse for Enchanted Slumber.