Episode 125 "Abby Road"- Abby's first day in the ER as a third year medical student.  She gets bit, helps out with a sting operation and almost kills a guy.

Episode 126 "Be Still My Heart" - Abby sees an elderly lady who is on the verge of death. She finds it hard to deal with the fact that in some situations heroic measures are not used, the lady later dies.  She tells Carter that this was the first old person she had ever seen die.

In Episode 128 "Be Patient", she saves a man's life after Kerry tells her to discharge him.  She had him come back so that another doctor could see him and he did.  Kerry told her that it was a good thing because he could have bled to death.

Abby's ex-husband Richard spends her tuition money for med-school, so Abby has to be an intensive-care unit nurse.  Kerry gets her to come and work in the ER.  We learn that she has an alcohol problem and she becomes Carter's AA sponsor, for awhile. 

Abby's mom Maggie comes to visit during the holidays.  She is bi-polar and causes Abby a lot of heartache.

Abby gets involved with Luka. 

Abby breaks up with Luka, because she thinks Carter may be interested in her.  Carter does not show any interest in Abby, because he is having something with Susan.  Susan can see though that Carter's mind is somewhere else, on Abby.  As the ER is being "Lockdowned" in the season finale, Abby and Carter share a couple of kisses, which according to seson 9 spoliers turns into a huge love affair.