Bubbie's Tummy Ache is the 29th episode in Season 1, alongside with the episode "Mind The Store, Don't Look in the Drawer"
Bubbie is having a severe stomach ache, and does not know why. She says that she hasn't felt as bad since the time she entered the Stormalong Pie Eating Contest. Flapjack decides to go down to Bubbie's stomach to give it a hug, and when he reaches the stomach, he meets a very old woman named Ruth who was sucked into Bubbie's mouth while she was baking pies. Upon conversing with Ruth, she tells Flapjack that she has taken up knitting, and he soon discovers that the reason Bubbie's tummy has been hurting is because Ruth keeps sticking her needles into Bubbie's stomach, causing her unbearable pain. Flapjack pulls the rope K'nuckles was supposed to be watching to bring them up, and it also falls into Bubbie's stomach, revealing a note: "Went to the Candy Barrel. See you soon. K'nuckles", leaving Flapjack and Ruth stranded. Ruth decides to teach Flapjack to bake pies to occupy their time, and the smoke from the oven (in addition to the horrible ingredients Flap uses) causes Bubbie to throw them both up.
- Bubbie can walk on land in this episode despite needing help earlier.