It's every parent's worst nightmare: your child goes missing. "Parental abductions come in more often than anything else," says Ted Davis, senior investigator for the Missing Children Society of Canada.

In years past a parental abduction may have meant one parent taking the child to a different city, or, at most, a different province in Canada. But a W5 investigation has found that along with increased cross-border marriages and travel at the click of a button. Gaps in existing border security means it's nearly impossible to stop.

W5 investigates cross-border custody battles as more parental child abductions go international. The investigation explains the flaws that allow for international child abductions to occur with more frequency from Canada than from some other parts of the world, the dizzying array of agencies left-behind parents are shuffled between, in their quest to bring their child home and what fixes could make a big difference in preventing these abductions in the first place.