Gate review 

In today's anime review, Youji Itami, an off-duty Japan Self-Defense Forces (JSDF) officer and an otaku, is on his way to attend a doujin convention in Ginza, Tokyo when a mysterious portal in the shape of a large gate suddenly appears. From this gate, supernatural creatures and warriors clad in medieval armor emerge, charging through the city, killing and destroying everything in their path. With swift actions, Youji saves as many lives as possible, while the rest of the JSDF directs their efforts toward stopping the invasion.
Three months after the attack, Youji has been assigned to lead a special reconnaissance team, as part of a JSDF task force, that will be sent to the world beyond the gate-now known as the "Special Region." Their mission is to explore this unfamiliar world, gather information about the inhabitants, and attempt to establish peaceful relations with the ruling empire. Failure to do so could result in a devastating war involving both sides of the gate.