Jalandhara was a demon king, born out of the union of the lightning from Shiva’s third eye and the Ocean. In one story, he accuses Shiva of hypocrisy, pointing out that Shiva claims to be an ascetic but keeps a wife, Parvati. Jalandhara proposes that Shiva hand over Parvati to him:
Shiva of course refuses, becoming so angry that a fearsome creature sprang from his brow and nearly killed Rahu, the messenger who had delivered the demand.
Jalandhara had a wife of remarkable piety named Vrinda (in some versions Tulasi). So pious is she that Jalandhara's misdeeds go unpunished under the protection of her virtue. Eventually Vishnu shatters Vrinda's chastity; a path is thereby opened to the punishment of Jalandhara, who is killed. To comfort Vrinda in her grief and despair, Vishnu promises her that a beautiful plant will grow from her grave, and that its wood would be used to make a garland (tulasi mala) for his neck.
An alternative version has Shiva using Parvati to corrupt Jalandhara, who is a virtuous demon. Vrinda curses Vishnu for his part in her husband's death; the curse is broken when Parvati plants three seeds in Vrinda's ashes which grow into three plants: the Tulasi, the Avali and the Malti.