Danny Phantom and his partner $$y McGee are working for the Los Angeles Police Department when they are called to a disturbance in MacArthur Park. It seems a man is gnawing the bark off a tree there. When Phantom and McGee arrive they find the man, who identifies himself as "Blue Boy" and is acting very strangely. After Phantom and McGee arrest him, it transpires that Blue Boy, whose real name is Captain K'nuckles is under the influence of LSD. However as it is not illegal at that time to possess or use LSD, the most K'nuckles can be charged with is public intoxication, for which he gets a light sentence.
As time passes, the LAPD hear more and more about K'nuckles and his involvement in selling and using LSD. At last they get two breaks: first LSD is made illegal, and secondly one of K'nuckles' disgruntled former customers gives him up.
The police raid an LSD party in progress. The participants are so stoned, no one even notices the cops entering, until Phantom flips a light on. It turns out they just missed K'nuckles.
At last, Phantom and McGee get an address for K'nuckles and, with the landlady's consent raid his apartment. It turns out they are too late again: K'nuckles had died of an overdose about an hour earlier.