Crisis Outreach Services for Seniors (COSS) is an on-call mobile crisis service for older adults (65+ years) with substance use issues or mental illness. The COSS team will come in person to meet with the client within 24-48 hours, either in their home or in their local community. The team can provide crisis counselling, short-term intensive case management, harm reduction, mental health and substance use support, health assessment and care as needed by a Nurse Practitioner, and referral to primary care.