Gintama S02 E03 If You Want to See Someone, Make an Appo First

"We're Odd Jobs Gin!"

It is revealed that the baby isn't Gintoki's; instead the baby was left at Yorozuya by the mother to keep her child safe from her father-in-law. Meanwhile Kagura and Shinpachi try to save the mother; Gintoki is on his way to return the baby.