As for the plot... Inuyasha is about a fifteen year old high school girl by the name of Higurashi Kagome who resides in a shinto shrine that has been taken care of by her family for generations. Kagome leads a fairly normal life until one day where she was pulled into the well on the shrine grounds by a monsterious centipede woman. After temporarily getting rid of the monster, Kagome climbs out of the well to find herself in the Sengoku Jidai, the feudal era of Japan (1467 - 1568).
In this ancient world, Kagome comes across a young boy who appears to be around the age of seventeen called Inuyasha and unseals him, revealing herself to be the reincarnation of Kikyou, the powerful shrine maiden whose duty it was to protect the Shikon no Tama (a mystical jewel offering extraordinary powers to any youkai or evil-hearted individual) fifty years prior to current events and was also the woman held responsible for sealing Inuyasha, again, fifty years ago.
When the Shikon no Tama is shattered into dozens of pieces, Kagome and Inuyasha are forced to team up together to recover all of the shards. Shortly after they team up, it is revealed that Inuyasha and Kikyou's relationship was sabotaged by a powerful and manipulative youkai known only as Naraku, who wanted posession of the Shikon no Tama. Their relationship, rocky at first, develops into a romance of sorts and they are soon joined by Shippou, an orphaned kitsune boy, Miroku, a Buddhist priest who is trying to kill Naraku in revenge for the curse put on his family and Sango, a youkai exterminator who wishes to exact revenge on Naraku for the death of her entire family.