Stephanie Huang, a minor, was injured when her hand became caught in an Otis Elevator Company (Otis) (defendant) escalator at a Sears, Roebuck & Company (Sears) (defendant) retail store at Price’s Corner. Hsu-Nan Huang (plaintiff), as guardian ad litem for Stephanie, sued Otis and Sears for negligence. Huang alleged that Otis and Sears were negligent in constructing, maintaining, and operating the escalator at the Sear’s Price’s Corner store and that the negligence resulted in Stephanie’s injuries. Huang also alleged that, at all times, Stephanie’s mother reasonably supervised Stephanie and kept a proper lookout for her safety. Otis and Sears asserted the defense of a supervening cause based on Huang’s negligent supervision of Stephanie, which they claimed was the sole—supervening—proximate cause of Stephanie’s injuries. Citing the doctrine of parental immunity, the trial court ruled that it would not allow any evidence or argument about Huang’s alleged negligence. Otis and Sears filed an interlocutory appeal.