Doc Baker realizes that something is wrong with the morphine in his pouches and he tells Nels that the company is very responsible and loyal and so something had to happen to it when it came here to Walnut Grove. He says no one messed with in the store and he had Albert drop it off for him. Doc Baker realizes that Albert must have switched the morphine for powdered sugar. He tells Charles to watch for symptoms of addiction. Charles finds the morphine in Albert's shoes and gives it back to Doc Baker. When Albert goes looking for it, Charles confronts him but Albert says he only did it once and he's sorry and it won't happen again. He lied and he has to go through a major major withdrawal to get off the morphine. Some of this episode is quite graphic where he vomiting up tons of grossness during the withdrawal.
Did You Know?
At the end of this episode, a voiceover from Laura tells us that:'Years later, Albert would return to Walnut Grove as Dr Albert Ingalls'. However, this is contradicted somewhat, in the TV movie "Look Back To Yesterday", which followed in 1983, when Albert is diagnosed with a fatal illness and dies before even getting into medical school and was followed by The Last Farewell when the whole town is blown-up. See more
Laura has a voiceover at the end of the Season 9 episode entitled "Home Again" in which she says that Albert comes back to Walnut Grove as a doctor later on. However, this is a highly debated issue because in the movie "Look Back to Yesterday", Albert contracts a rare blood disease and it is inferred that he died, although that is also debated. So he could not come back and be a doctor if he died at the end of LBtY.
Also, in the movie "The Last Farewell", the residents of Walnut Grove blew up the town. Therefore, unless they rebuilt the town, Albert couldn't come back to Walnut Grove to be a doctor, because nothing was there mostly except ruins. See more