Fam and Ihrie are willing to do almost anything to make a buck. So when these debt-driven damsels discover the potential profits to be hand in recovering a particularly dangerous mystical object, it means mortal peril for an entire civilization. There's no guarantee that they'll live long enough to squander the fabulous wealth they've been promised, and danger lurks around every turn as they cross dark seas in pursuit of legendary evil. Haunted by an unspeakable curse, plagued by doomsday prophecies, plotted against by untrustworthy traveling companions and looked in desperate race to gain the Ultimate Power, Fam and Ihrie are the Ruin Explorers!

Saito High is a high school with its spiritual beings and a principal whose hobby is collecting occult paraphernalia. The school has the prophecy-chosen members of the Holy Student Council to protect it. These students have problems of their own; Haruto Houjo, the president, has a way of summoning spirits, and would resign from his duty for a normal life if it weren't for the principal. Kazumi Ryodo, the next member, is good at being possessed and has something for the Hanako. The last member is Mutsuki Asahina, who is a master of exorcism and is attracted to small boys. Unfortunately, these three are in charge of keeping the school in line and defending the world from supernatural beings, and this mission brings them through wacky predicaments.

The half-divine King of Uruk, Gilgamesh, was considered but a paltry legend... until his majestic tomb was discovered in the Middle East. This imperial crypt drew scientists from across the globe to the land, and with that came recognition of their fame. In a joint effort, they built Heaven's Gate in pursuit of advancing human knowledge. One day, a group of terrorists driven by greed attack Heaven's Gate, causing an explosion within the facility for archaeological excavation. The resulting phenomenon had much more impact than anyone could have imagined. More specifically, it triggered the birth of supernatural beings. In the midst of this mess, two siblings by the names of Kiyoko and Tatsuya encounter mysterious men with supernatural powers who, despite the scientific crisis around them, claim the ability to restore good to the world. Nevertheless, these seemingly heroic and all-powerful creatures act under the rule of factions. Are they here to save the world, or destroy it?

In a small town, there is a small pharmacy called Fun Fun Parmacy. Popuri, a girl who recently moved in downtown, discovers this pharmacy and meets Miss Fukiko, who is actually a witch. Miss Fukiko gives Popuri a mysterious bottle that can create magic spirits.