In the second part of the two-hour fourth season premiere, The SWAT team acts as a domestic surveillance unit for the CIA to confirm whether an international crime lord has resurfaced in Los Angeles after being off-grid for years. Also, Tan's mother, Chan Fei (Susan Chuang), is a victim of racial discrimination, and Hondo encounters his ex-girlfriend Nichelle (Rochelle Aytes), for the first time since their breakup.