This study will deploy a scalable secondary prevention program that leverages existing foster youth transition services to improve mental health functioning and service use before and after exiting foster care. Our short-term objective is to remotely test a group intervention called Stronger Youth Networks and Coping (SYNC) that targets cognitive schemas influencing stress responses, including mental health help-seeking and service engagement, among foster youth with behavioral health risk. SYNC aims to increase youth capacity to appraise stress and regulate emotional responses, to flexibly select adaptive coping strategies, and to promote informal and formal help-seeking as an effective coping strategy. The proposed aims will establish whether the 10-module program engages the targeted proximal mechanisms with a signal of efficacy on clinically-relevant outcomes, and whether a fully-powered randomized control trial (RCT) of SYNC is feasible in the intended service context. Our first aim is to refine our SYNC curriculum and training materials, prior to testing SYNC in a remote single-arm trial with two cohorts of 8-10 Oregon foster youth aged 16-20 (N=26). Our second aim is to conduct a remote two-arm individually-randomized group treatment trial with Oregon foster youth aged 16-20 with indicated behavioral health risk (N=80) to examine: (a) intervention group change on proximal mechanisms of coping self-efficacy and help-seeking attitudes, compared to services-as-usual at post-intervention and 6-month follow-up: and (b) association between the mechanisms and targeted outcomes, including emotional regulation, coping behaviors, mental health service use, and symptoms of depression, anxiety, and PTSD. Our third aim is to refine and standardize the intervention and research protocol for an effectiveness trial, including confirming transferability with national stakeholders.