In the finale, she gives her blessings to Marshall and Abigail.
Mc Cormack also made a guest appearance as Mary Shannon in the Law & Order: Criminal Intent episode "Contract".
At the start of the fourth season, Mary had already ended the relationship with Faber in order to give him the opportunity to try to work things out with his ex-wife.
In the season finale, a two-part episode including "Stan by Me" (1.11) and "A Fine Meth" (1.12), Mary is kidnapped and Brandi is nearly arrested for distributing drugs, leading the family to begin recuperating.
During the second season, Mary's family continues to annoy her, but she can see past it more often.
She becomes engaged to Raph, though she has feelings of uncertainty at times.
She is, however, able to trust him enough to reveal the true nature of her job to him.
They eventually do, but Mary is still in danger of losing her life.
The third season opens with Mary being released from the hospital, very much alive and ready to get back to work. Soon, Mary meets FBI Special Agent Mike Faber, who asks her on a date. Soon, Mary and Brandi's half brother, Scott Griffin enters their lives.
In the sixth episode of the fourth season, "Something A-mish", she finds out that she is pregnant by Mark after one night together.
The pregnancy of Mary is written in to incorporate the real-life pregnancy of Mary Mc Cormack.
Mary becomes increasingly annoyed with Brandi, and it comes to a peak when she actually hands the money over to Scott.
By the season finale, "A Priest Walks Into a Bar" (3.13), Mary and Faber had started dating.
Throughout the season, a new office manager, Eleanor Prince, is hired.