Tokimeki Memorial 2 takes the basic story of the first game where you are playing a male student through his 3 years of high school but this time when you first play you start out as a kid who then later moves away. (summary from http://kojioe.wordpress.com/2009/02/23/tokimeki-memorial-2-nostalgia-review-part-1/)

An original set of extra stories set in the TM2 timeline, inspired by the Drama Series from TM1 but with different gameplay. DSV is set in the summer of the first year of high school. While hanging out with the player, Kotobuki Miyuki got an enormous score in DDR and is invited to a national tournament. Believing it to be a fluke, she'll ask the protagonist to train her, and thus a summer of dancing begins. Shirayuki Miho and Yae Kaori also eventually become involved.

An original set of extra stories set in the TM2 timeline, inspired by the Drama Series from TM1 but with different gameplay. MRO is set one year after graduation, with the protagonist remembering his school days at a coffee shop. He mostly focuses on his last Valentine's Day in high school, and how several girls acted that one day.