The first four episode descriptions were posted here!
1.05 - Ghost on the Highway (New Episode)
Sam and Dean are driving along the highway and are suddenly chased by a cop car from behind. They discover that there have been numerous unexplainable car accidents in the area. All accident involved a Chevy Impala. Sam and Dean have to investigate to prove themselves innocent. We discover that an evil spirit has taken the form of an Impala is trying to take revenge on the town.
1.06 - Bloody Mary (New Episode)
Back in 2004, when Sam was studying at Stanford. Sam hears about a suspicious death case occurred in Stanford from Jessica, a girl he's becoming friendly with. John and Dean smell something evil in the case and start investigating behind Sam's college life. They first presume that it is caused by a ghost called "Bloody Mary" but it turns out to be caused by a different ghost.
1.07 - Temptation of Demon (New Episode)
Maria, a faithful Christian is lured by a yellow-eyed demon to become its servant in return of curing her sick daughter. She refuses at first, but is quickly drawn in.
1.08 - Everlasting Love (New Episode)
Multiple homicides in Illinois. The victims are all blond women in their 20s and the crimes scenes leave traces of formaldehyde. Sam and Dean discover fingerprints of a female who died in 1940. A tragic love story of a mad doctor.
The animation series seems to depart more and more from the original canon as it progresses. Innnnnteresting.