A virus has ravaged the planet, wiping out the adults. The children live in savage packs. In Sicily, hidden away in the woods, are the Salemi siblings: Anna and Astor. One day, Anna stumbles across a gang of children smeared in blue paint.

After taking care of Astor, Anna sets off in search of provisions. She decides to go and look for Pietro, who lives on the shores of a lake. A gang of blues, drawn by a fire Astor lit, turns up at the farm and force him to Angelica's villa.

Astor is dipped in blue paint, making him one of the evil Angelica's followers. Meanwhile, Anna has been imprisoned in the supermarket basement, but tries to make an escape after Pietro comes looking for her, desperate to find her brother.

After the night's revelry, Anna searches for her brother, but Astor wants to stay with the blues. In attempting to escape, Anna is bitten by a viper and passes out. When she wakes up, she finds herself face to face with the Big Little Lady.

Anna and Katia prepare for the wedding ceremony. When Angelica checks in, she falls into their deadly ambush. Katia decides to stay at the villa and Anna sets off alone. When she reaches Pietro, she learns devastating news.

When Astor dreams of his mother, she tells him to go back to his sister. Anna returns home, broken, but reunited with Astor. The siblings decide to set off for Italy, hopeful that someone has managed to find an antidote for the Red Fever.