Melissa Ponzio as Melissa McCall -Human-
Melissa McCall (née Delgado) is Scott’s cynical but comforting and loving mother. Melissa is close friends with Stilinski and is like a surrogate mother to Stiles. Melissa works as an R.N. nurse at the local hospital, Beacon Hills Memorial Hospital. Scott is very close to his mother, especially since his father Rafael is no longer in the picture. In “Formality”, Melissa helps Scott get ready for the school formal and tells him “Women love words”, giving her son the confidence he needs to tell Allison both he loves her, and that he’s a werewolf. In Season 2, episode “Abomination”, Melissa’s life is threatened by Gerard Argent to blackmail Scott into following his orders. Scott complies, though Melissa notices his distress immediately afterward. Scott lies to her, saying everything’s fine. In “Restraint” after Jackson files a restraining order against Scott and Stiles, Melissa angrily confronts Scott over all of his bizarre behavior and concernedly asks are his actions are because of his absent father. To keep her in the dark, Scott affirms this. In episode “Fury”, Melissa is called to the sheriff’s station as a witness, but as she arrives she sees Matt, the Kanima’s Master, shoot Scott in the stomach and is horrified. Melissa is held hostage with Stilinski. Melissa finally comes into contact with her son’s world, witnessing Derek, in werewolf form, fight the Kanima along with seeing Scott in his werewolf form. At first, Melissa is devastated, shocked, having trouble coping, avoiding Scott for a week and is even more frightened when Gerard breaks in and has the Kanima hold her hostage. Eventually, she comes to accept Scott for what he is and encourages him to help others with his abilities.
In Season 3, Melissa is closer to Scott having somewhat come to terms with the supernatural, assisting him in the dangers in Beacon Hills, attempting to smuggle Isaac out when he’s committed to the hospital and helping Stiles identify a new killer in Beacon Hills by allowing him access to the morgue. In the episode, “The Overlooked”, during the evacuation of the hospital because of a thunderstorm, Melissa finds Ethan and Aiden in their merged form attacking Scott. She saves her son by electrocuting the twins with a defibrillator. She helps Scott the others with their plan to help Jennifer, the Darach, escape the Alphas (Jennifer had poisoned Cora and kidnapped Stilinski for leverage), but Jennifer double-crosses them and kidnaps Melissa. Melissa is later held in the Nemeton along with Stiles’ and, later, Allison’s fathers for the final sacrifice, Guardians. In “Lunar Ellipse”, she and the other parents are rescued by Isaac, Allison and Stiles. Like Scott she is not happy with her ex-husband and Scott’s father, Rafael back in town. In “Anchors”, Melissa, along with Scott, is angry when Rafael conducts a case for impeachment in his attempt to fire Sheriff Stilinski. Right afterward she realizes Scott is about to lose control of his wolf side. More used to the supernatural, she helps him regain control by telling tell him to “be his own anchor”, as Allison was his anchor and they’ve parted which Scott manages to do. After that she comforts and promises him that people fall in love more than once. Melissa has also had the McCall residence installed with ash wood base boards with Deaton’s help to work as wards against supernatural intruders which she arms when the Oni attack the house. Mellisa, Stilinski and Scott’s issues with Rafael are revealed in “Insatiable”: when they were married, Rafael used to be a heavy drinker. One time, when Scott was only a toddler, Rafael came home drunk and got into an argument with Melissa. Rafael had accidentally knocked Scott down the stairs bruising his head on the floor and she had kicked Rafael out. She’d confided in Stilinski, whom later became an alcoholic following his wife’s death, exacerbating spite from Rafael. In the Season 3 finale, the hospital is attacked by the Oni, and Melissa makes Rafael promise her, if she doesn’t make it, he is to make things up with Scott. Melissa is saved when the Oni are destroyed and the Nogitsune is defeated.
During Season 4, because of the financial crunches in Beacon Hills due to all the damage done to the hospital, and the killing sprees, Melissa is late in paying her bills for the house, forcing her in having to make double shifts at the hospital and she calculates the cost of the budget to learn how long before she and Scott lose their house. Scott, worried for Melissa, hides the duffel bag full of Dead Pool money, paid to the assassin Garrett, in his room, hoping it could solve their financial crunch. In “Time of Death”, Melissa harshly breaks down in response to Dr. Geyer telling her Scott is “dead”, but she knew it was part of a plan to flush out ‘the Benefactor’. Melissa, with Noshiko Yukimura’s help, is able to feel Scott’s suppressed heart rate to reassure her he’s really alive, he just appears dead. She says she hates the plan when told Scott will die for real if Kira doesn’t shock him again within 45 minutes. Melissa asks Noshiko why are they, as parents, letting their kids handle these dangers. Noshiko answers her, that they’ll be asking them to “run and hide” instead. Melissa finds the duffel bag of money in “A Promise to the Dead”, and confronts Scott, saying while he can “save lives”, he can’t save people “from life”, convincing her son to return the money to the Hales.