It's time for young Adam to be tested by The Witches' Council to see if he has magical powers or not. If he proves to be merely mortal, it is decreed that he will be taken away from his parents and sister. Maurice, unsure whether or not his beloved grandson is a warlock, imbues Adam with some powers so that he is able (Maurice hopes) to fool the council into believing that he is magical, even if it turns out that he isn't.
Happily for everyone concerned, Adam is indeed deemed to have magical powers wich he is able to show without any magical assistance from his grandfather.
The episode is somewhat repetitive as we have been there and done that several times throughout the seasons with different characters but it's a nice episode given that we are able to see that both Samantha and Darrin's children are magical like their mother.