dad refusing legal mother right to be with child after he took child and moved in wit

The legal dad got mad at legal mom and left legal residence with child to stay at his moms home. Now the dad and mother in law are refusing the legal mother access to her child. What actions have to be taken to force these wackos to allow the legal mother access...there is no pending divorce or seperation and the father is just punishing the mother cause she refuses to follow his wishes on minor details about her new job...

Go to the courthouse and file an emergency ex parte petition to have the child returned.

if my legal residence is in say dallas county and my husband has taken my child to say collin county to his moms... what county do I need to file the ex parte in??? by the way thank you so much for your input...