The game is set in Sumaru City, Japan. A rumor is going around the city that if someone calls their own cell phone, a mysterious figure known as the Joker will answer, and grant the caller a wish. The game centers around Tatsuya Suou, a student at Seven Sisters High School; when he and his friends Eikichi and Lisa call the Joker, tragedy ensues. The three teens begin their own crusade to find out the truth behind the Joker ritual, aided by reporter Maya Amano and photographer Yukino Mayuzumi (from the first Persona). They find that the answer lies much closer to home than they'd thought...
First, the good: The plotting of the game is quite well-done. Engaging characters and an intriguing plot will keep you playing, and the gameplay is deep but easily learned, and the battle system is quite polished. The music is alternately wonderful and "bleah!", but the quality songs prevail.
The bad: When the songs are bad, they're really bad. Everything in the menu and battle systems seems to take one or two more button presses than should be necessary. Many gamers raised on the Final Fantasy series will find that this game may be sort of hard (it requires much more strategy than a lot of RPGs). And finally, the game is in Japanese, with no U.S. release on the horizon.
If you do understand Japanese even a little, and like console RPGs, I highly recommend this game. If you don't understand Japanese, I recommend its sequel, Persona 2: Batsu (released as Persona 2: Eternal Punishment in North America), instead.