Timon leads Pumbaa on a wild goose chase around the Canadian Rockies to search for Pumbaa's new bug friend who Timon believes he accidentally ate.
"Rocky Mountain Lie" begins by introducing Timon, a meerkat, and his warthog friend Pumbaa. At the start of the episode, Timon and Pumbaa are snowed in at a cabin in the Rocky mountains. Timon is unable to open the front door until Pumbaa suggests he pull it instead of pushing it. After Timon and Pumbaa successfully open the door, Timon expresses his hunger, since bugs are scarce in the snow. The pals split up to cover more ground. Timon spots a rock, but underneath, he finds no bugs. He is unable to find anything but an angry grizzly bear. As he runs from it, he is buried in falling snow from a tree.
Meanwhile, Pumbaa easily finds a bugsicle and takes it back to the cabin. It thaws and the bug is freed. Pumbaa waits for Timon to return home, but decides to eat his half of the bug now. But before he is able to dig in, Stinky, the bug, sneezes and Pumbaa confusingly responds, "Bless you." Stinky relays his sad story to Pumbaa of being kicked out of his band by the other three members, due to him being a stinkbug. Because Pumbaa relates due to his stinkiness, he allows Stinky to remain there to sleep off his cold while the warthog goes out to collect more wood.
While Pumbaa is gone, Stinky's former bandmates show up to invite him back to the group. He leaves with them just before Timon re-enters. He ravenously devours a bug thrown away by a spider. Pumbaa returns home with a stack of firewood, asking Timon if he has seen his bug friend. Timon, believing that he ate Pumbaa's new bug friend, replies by saying he hasn't seen the bug. Pumbaa begins sniffing around, and reveals that his missing pal is a stinkbug. Upon hearing this news, Timon passes out.
In his nightmarish vision, Timon is condemned by a court full of stinkbugs to death for his crime of lying. His head is put in a guillotine and he awakens with his head through the floor, believing he has been "decaffeinated." Pumbaa pulls him back through into the room and Timon expresses his guilt for what he did. To alleviate the guilt, he tells his pal that Stinky was kidnapped by a grizzly bear.
Pumbaa rushes out into the winter wonderland. Timon attempts to trick his buddy into believing he is actually beating a bear in the cave. Pumbaa is proud of his friend, but when Timon exits, a real bear is standing behind Pumbaa. Timon and Pumbaa narrowly flee from one bear, but then crash into three more.
Meanwhile, Stinky is kicked out of the band once more by his mates. He sees Timon and Pumbaa on the bears' platter, and desires to help. He sneezes and takes a tumble down the hill. He rolls into a snowball and crashes into the predators, scaring them away. Pumbaa is elated to see his bug friend again, and Timon finally reveals that he believed he had eaten Stinky and lied about what happened to him. When Pumbaa hears this, he accepts his friend's apology. As a kindness, Stinky promises Timon and Pumbaa some bugs to eat: his ex-bandmates.