Firearms are the leading cause of death for U.S. youth. National organizations have highlighted the need for prevention programs focused on decreasing interpersonal firearm violence. Urban EDs are an underutilized setting for such programs, as they provide access to at-risk youth engaged in risky firearm behaviors (RFBs). Intervening early with youth in this setting may decrease subsequent firearm violence and related consequences. Despite the importance of this problem, evidence-based interventions to decrease RFBs are lacking. Given our prior work showing that single session ED interventions (i.e., SafERteens) integrating motivational interviewing (MI) and cognitive behavioral therapy (CBT) are efficacious reducing violence among lower risk youth, the application of this behavioral therapy, expanded to address greater problem severity over multiple sessions and enhanced by adding care management (CM), represents a potentially efficacious approach for decreasing RFBs. Our pilot of this integrated approach was found to be feasible among high-risk youth engaged in violence. Utilizing centralized remote therapy to address identified in-person therapy barriers (e.g., transportation) and supporting the intervention with an APP may be a promising way of enhancing session attendance, intervention dose, and engagement, while considering future implementation issues. This proposal addresses Objective Two (Funding Option B) of the CDC NOFO as it focuses on collecting new data on strategies to decrease firearm violence. We propose a 2-arm randomized control trial (RCT) enrolling ED youth (age 16-24) reporting past 3-month firearm carriage and smartphone ownership, randomizing them to either: (1) IntERact; or, (2) an enhanced usual care + assessment (EUC+A) condition where they will receive a resource brochure and daily assessments. The IntERact condition will receive: (1) 6 remotely delivered behavioral therapy sessions integrating MI, CBT, and CM; and, (2) an smartphone APP supporting the therapy by facilitating therapist contact, conducting automated daily assessments, delivering between session tailored MI/CBT content, delivering just-in-time GPS-triggered notifications upon entry into high-risk locations, and aiding with CM resources. Specific aims are: (1) To conduct an RCT enrolling 400 eligible youth (200/group) to examine IntERact efficacy; and, (2) To conduct a cost evaluation, comparing resource costs for intervention delivery to costs for outcomes averted. As a secondary aim, we will examine mediators/moderators of efficacy. Outcomes will be assessed at 3- and 6-months. Primary outcomes include: (1) risky firearm behaviors (RFBs); (2) firearm carriage; and, (3) violence (i.e., aggression; victimization; consequences). Secondary Outcomes include: (1) ED visits for violent injury (e.g., firearm injuries); (2) substance use; (3) mental health symptoms (i.e., anxiety, depression, PTSD); and, (4) criminal justice involvement (i.e., arrests). Given el...