In 2015, Mylan Inc. and other affiliated companies (Mylan) (plaintiffs) formed a parent holding company, Mylan N.V. This parent holding company was represented by Kirkland & Ellis LLP (defendant) in a number of the company’s endeavors. Teva Pharmaceuticals Industries Ltd. hired Kirkland to represent it in connection with a hostile takeover of Mylan N.V. Teva and Mylan were pharmaceutical industry competitors. Kirkland conducted its standard conflict of interest check and confirmed it could represent Teva because Mylan N.V. had never been a client. Kirkland established an “ethical wall” that isolated the lawyers working on Teva’s hostile takeover from those lawyers who had previously represented and would continue to represent Mylan. Mylan N.V.’s board of directors rejected Teva’s takeover offer. Mylan brought suit in the Pennsylvania Court of Common Pleas, alleging that Kirkland violated its fiduciary duties to Mylan under the Pennsylvania Rules of Professional Conduct. Mylan moved for a preliminary injunction, seeking to enjoin Kirkland from further representation of Teva in the attempted hostile takeover.