Bobby's return was supposed to be a secret but clearly, "Supernatural" was not successful in keeping it that way. Although the surprise return of the Winchester brothers' best pal and father figure was given away, it does not take out the excitement of seeing him one more time. 

In the next episode of the long-running series titled "Inside Man," Rowena seeks his help from heaven. His rare and rather celebratory appearance is crucial to the wellbeing of Dean, who still has the Mark inside of him. 

Bobby, who is portrayed by Jim Beaver, was killed off in season 7, in the episode titled "Death's Door." He has occasionally popped up in several episodes as a ghost. 

Meanwhile, Sam and Castiel do everything necessary to get rid of the curse in Dean's system, even if he refuses help or accept the fact that he needs it. Sam "knows his brother very well" and he would not need a verbal signal or a cry for help to know that his brother is in trouble. 

"He knows his brother is too gruff and tough to admit all the time he needs help, though he has, here and there, finally broken down and said, 'Yeah, I could use a hand.' So he is going to do what he thinks is best for his brother," Jared Padalecki, who stars as Sam in the series, told Variety. 

Sam cannot simply ignore his brother's troubles and he vows to do everything just to get him to safety, even if it means doing it behind his back. In the promo for the episode, the young Winchester enlists the help of an angel for his big brother who is "getting worse." 

However, in the same footage, it looks like Rowena knows how to cure Dean. But it is unlikely that Sam will ever seek the help of someone who he thinks is a threat. 

Episode 17 will also feature Metatron begging desperately to an angel to let him live. 

"Supernatural" season 10 episode 17 titled "Inside Man" will air on April 1.