Howard's father comes back into his life and it is difficult for Howard to forgive him for his abandonment and so the gang try to help.
PREVIOUSLY... Howard and Berndatte are showing their friends the sonogram and then the doorbell rings and then Howard goes to answer the door and when he opens it, he says "Dad?".
CONTINUING... Howard is again at the door and is stunned at who he sees. It's his father Sam along with Josh and Sam's second wife and Josh's mother, Iris Wolowitz.