Christopher Nolan’s latest blockbuster is hitting theaters this summer. It is, of course, The Odyssey . The movie is an adaptation of an ancient epic poem written by Homer (probably — more on that below). For those of you who haven’t yet read Homer’s masterpiece, or who have only dim memories of it from long-ago classrooms, we wanted to bring you a primer on exactly what you’ll be walking into when you sit down in front of that IMAX screen. Note that Nolan’s film is sure to differ in some ways from the source material. Time ’s new interview with Nolan lays out several of the major changes. Among these is a bigger role for Odysseus’ long-suffering dog Argos, who in the poem appears in just one short — but absolutely gut-wrenching — scene. With that in mind, dry your tears, pick up your swords, and get ready for a crash course in the basics of The Odyssey. The events of the epic span a decade-long period, starting just after the Trojan War.…