It seems that Peter will have a tough time in the upcoming episode titled "The New Adventures of Old Tom" as after his family abandons him, he gets lost in a mall.
CLICK HERE to watch how Peter will find a way out of the mall and why his family left him in the mall in the first place.
According to the synopsis of the episode by Family Guy Wiki, "Peter gets lost in the mall overnight after his family abandons him. Meanwhile, Brian pretends to be a millionaire to win over a girl."
In the previous episode titled "Take a Letter," when Lois became concerned about Stewie's day care, she wanted to send him to an exclusive preschool. While at the post office, she found that Cleveland had a job with them and took his suggestion to come work for them when she admitted they need money.
On her first day, Cleveland showed her around and provided tips on snooping through the mail. When Mayor West dropped off an undeliverable letter, she offered to sort through the dead letter bin and see if she can properly match the correct address on some. While doing this, she found a letter from Peter to a woman dated just a week before their wedding.
She took her concerns to Bonnie who suggested that she mail it to see what it may be about. She delivered it personally and met Gretchen; Peter's ex. Gretchen told her that Peter was happy to be getting married to Lois, hence she broke up with him.
Gretchen showed up at the Griffin home and revealed that the letter really said that Peter had doubts about his impending marriage and she pressured him to start their relationship again at the risk of her informing Lois of the letter's true content.