Timeline (2003) on Netflix

In the heart of the beautiful and historically rich Dordogne Valley of France, a team of archeology students and their professor diligently work to uncover the ruins of a 14th-century castle. For Professor Edward Johnston, the project is the culmination of a lifelong dream. Aided by assistant professor Andre Marek, his son Chris and students Kate, Stern and François, Johnston has made major strides in unearthing not only La Roque Castle but also a monastery and structures from the surrounding village of Castlegard. But things are about to go haywire... Suspicious of the dig's benefactor, International Technology Corporation (ITC) and the man who runs it, Robert Doniger, Professor Johnston heads to ITC headquarters in New Mexico to get some answers, and while he's away, his students discover a chamber that has been sealed for more than 600 years. Marek and Kate descend into the unstable room, and just before a near disastrous cave-in, they make two startling discoveries -- a bifocal lens, which couldn't have been invented before the chamber was sealed, and even more intriguing, a handwritten plea for help dated April 2, 1357...from Professor Johnston! Determined to solve the mystery, the students head for ITC headquarters, where they are stunned to learn of Doniger's new invention -- a machine that can actually transmit three-dimensional objects through space. Although he meant for the device to revolutionize shipping, Doniger inadvertently opened a wormhole that leads directly to the 14th century, and Professor Johnston, who had insisted on experiencing the discovery himself, is now trapped in a vicious French vs. English feudal war! Can Johnston's loyal students survive one of the most violent battles in world history... and make it back to the 21st century alive?