Family group chats are a popular form of technology-mediated communication. Family group chats represent an understudied area of family communication. In this qualitative multi-method study, I aimed to investigate how and why families use family group chats and how family processes are enacted within them. This grounded theory study was informed by family systems theory and uses and gratifications theory. Families participated in multi family member group interviews and were invited to submit the last one-month's history of their family group chat. Forty-nine participants from thirteen families across the United States participated in this study. I identified four themes from the data: (1) entering the chat, (2) growing and aging with the group chat, (3) accepting terms and conditions, and (4) holding the invisible string. I present a theoretical explanation of how these themes interact. Family group chats held a significant place in family life that extended family members' availability to one another and kept them in near constant contact, even when they were separated by geographic distance. I propose the possibility of family group chats as a protective factor to increase family functioning. This research generates future directions for the field and has implications for families, professionals who work with families, and group chat application developers. It provides one of the earliest investigations into family group chats from a family science perspective.