Legal Question in Family Law in California

File an ex parte motion asking the judge to have the children returned to California.

A key question is whether she was served with the filing before she left. If so, she is in contempt of the automatic restraining orders that are printed on the summons and go into effect as soon as you file as to you and as soon as she is served as to her. If so you can get a contempt citation issued against her which will expedite things in TX. You should also file a child abduction police report. If you have not yet served her, then Ms. Kock is correct, you need to file a motion for an order that the children be returned to California. If you serve that order on her in TX and she refuses, then you will have to have the order enforced by TX authorities under TX law governing enforcement of out of state orders (a fairly common and routine process but not necessarily a simple one; you'll need a lawyer in TX).