For a while, Tara’s character then suggests a darker path – when she deliberately prevents Willows “Demonic Energy” locator spell from working. In this spell, Willow mixes a potion and tells Tara that they should each blow half onto a square map representing Sunnydale (which will then glow different colours to show where various demons are located). Tara prevents the spell from being cast, by throwing her half of the potion under her bed instead (whilst Willow has her eyes closed). It turns out that Tara has a secret to protect – she believes she is part demon, and wishes to hide this fact from Willow. This hiding comes to a head when Tara’s family comes to town: she’s so afraid of loosing her new found friends that she casts a spell (so that they may not see the demon part of her).
The spell involves Tara speaking an incantation, that places a curse upon her friends, being cast when some swirling yellow smoke (that’s blown from Tara’s hands) touches their faces. Unfortunately, consequences arise, and Tara’s spell is more effective than she intended – as Buffy and the rest of the scoobie gang are unable to see the monsters that are attempting to kill them. Fortunately, Tara realises the consequences of the spell she cast, and reverses it just in time for Buffy to save the day. Tara admits what she did, then prepares to leave her friends (by leaving Sunnydale with her family). Eventually, it is found that Tara is human, and that her demon side was all part of a family legend (a lie used by her family just to keep their “women in line”). Tara then becomes an important part of the scoobie gang (helping them with friendship, research and magic).