It is part of the Shining Force series originally created by Hiroyuki Takahashi and Yasuhiro Taguchi. The two books in this game are remakes of games previous released on the Sega Game Gear): Shining Force Gaiden and Shining Force Gaiden 2: Sword of Hajya. The games were altered to include improved graphics and sound in what became Shining Force CD.
Although Guardiana/Gardiana initially sent out a force beforehand, no word of them had been received. So Lowe, advisor to Queen Anri (and best friend of Max from the first Shining Force), decided it was best to send out another force, which is the force you control. The force then travels to Cypress, meetings friends and enemies along the way, and also discovering secret things about Nick, the visitor to Guardiana/Gardiana which you control.
During the development of the game, you learn Nick's true identity: He is the Prince of Cypress. His father, the King of Cypress, was killed by Woldol and his brother Edmond, who then assumes the throne of Cypress. After Guardiana/Gardiana first discovers this, they are suspicious of Nick, but after meeting the Warrior Gyan at the Port Town of Cypress, who explains the cituation of Cypress to the Guardiana/Gardiana forces, they trust Nick again. The force continues onto Cypress castle, killing Edmond along the way, rescuing Luke (who is incorrectly called Lug in this game - Luke was one of the original members of the Shining Force of the first game), and defeating Woldol. Before they actually battle Woldol, he, using the power of Iom (the god whom he worships), turns himself into a giant scorpion. In this form, Woldol can only be attacked by Nick who wields the Sword of Haiyja, after of course, the sword is given to him by Luke/Lug. Unfortunately, when Nick first attacks Woldol, Woldol attacks back and ends up poisoning his (Nick's) right arm. After defeating Woldol, Nick's arm turns to stone.
Thus peace is restored to Cypress and Guardiana/Gardiana, and Queen Anri is released from her poison. This sets up the continued story of Book 2.
After finishing both books, a third book can be accessed. Due to the memory limitations of the Sega CD console, saving progress made in book 3 must be saved on a back-up RAM cart since the Sega CD's internal memory isn't enough to save both games data.
(To see a full transcription of the stories from all three books, go visit here)