Plot hole: In this episode, the Duboises make such a big deal about Ariel being old enough to finally learn to drive. However, two episodes previously ("Things to Do in Phoenix When You're Dead") Ariel drove herself to school and Joe complimented her on her prowess.
Plot hole: Joe says that he and Allison told people they conceived Ariel on the weekend of their wedding, even though they knew that Allison was about five weeks pregnant at that time. In episode 6.15 the plot is all about how Allison is expecting Ariel and there is a lot of talk of how she is their first child and they can't tell anyone about it because they aren't married yet. But in the season two episode "Sweet Child O' Mine" it was revealed that they were going to have a baby once before Ariel, a boy they were going to name Brian, but that Allison miscarried.
Plot hole: It seems strange why Alison and Cynthia Keener don't raise any suspicion with Wheeler's mother after rescuing her daughter Joanna. After Keener finds her and the other missing girl, she says to Alison that the kidnapper had taken them and had been torturing and abusing them for a number of days. However when Alison and Cynthia go to talk with Wheeler's mother about the old kidnapping case (before the two were rescued) the mother states that she has never been kidnapped and had even saw her yesterday. While the mother might not have been aware of her daughter's kidnapping, wouldn't she have been a little perplexed to have found her daughter had been kidnapped and tortured during days she had seen her. Even if this was something that was not shown, why wouldn't Alison and Cynthia (someone who is well trained in kidnappings) find the mother's statement combined with the kidnapping a bit strange.