This is an AU LINSTEAD story! Jay Halstead is working in the Intelligence Unit, and has a four year old daughter. He begins working with Erin Lindsay, a social worker, who took on the case as a favor to Voight.
Jay witnesses an unhealthy family dynamic and brings his 16 year old sister to live with him. The sweet and innocent girl he remembers is now full of sarcasm and secrets. But there's never a mystery that Jay can't solve, and he's determined to get answers. AU, sisfic.