Micky is on the beach with his girlfriend Brenda, a pretty blonde but empty-headed girl, when a big blonde bully of a muscleman named Bulk arrives, kicking sand on Micky, and tries to impress Brenda with his muscles. When Micky tries to intervene, Bulk overpowers him by shoving him away in the sand where he encounters Shah-Ku, a physical cultist who hands Micky a card that advertises his body building course. Micky rejects his offer and tries to fight the Bulk only to be overpowered once again while the muscle guy walks off with Brenda. Shah-Ku tries to initiate him once again to join his club but Micky tries to tear up the card…and finds he can't!
Micky goes with Shah-Ku back to his gym where he tries to convince Micky he's a weakling and to prove his point puts Micky to three tests where he does his level best to see that Micky fails at them. Micky climbs a rope that's greased, uses pulleys which yank him into the wall, and lifts a dumbbell that's too heavy. After failing, he convinces Micky to join his health plan for $150 for member-ship. Micky is bewildered as to how he, an unemployed drummer, can conjure up such cash; Shah-Ku suggests he hock his drums. Back at the pad, David and Peter try to convince Micky not to hock his drums since they have little money and food already and try to convince him to use their own physical program. Peter tries to show him how to use strength pulleys which he can't use himself. David tries to show him a muscle exercise for his back but finds that he can't straighten himself out. After a jog on the beach (where Peter rams into and bounces off a volleyball net), the guys surprise Micky for sticking to his training by inviting Brenda over, but Micky is too exhausted to be able to impress her.
Early the next day, Micky feels ready to take on Bulk, but David and Peter decide to handle it without violence and conjure up underhanded tactics to get rid of the Bulk instead. On the beach, David confronts Bulk and dares him to step on over a series of lines he makes on the beach while Peter paints red spots on his back. Afterwards, David beats a hasty retreat and Peter returns, garbed as a doctor, to try to convince Bulk he's wasting away. After examining him with a stethoscope and a mallet he tells him he'll lose his strength before charging him $10. Later, Davy and Peter toss a ball at him and ask him to throw it back but the Bulk can't lift it since it's made of lead. Then David disguised as a little kid asks the muscle man to hold his kite for him but when does so he is pulled into the sky by a dirigible heading for Bayonne, New Jersey. Back at the pad, Micky is still skeptical of getting Brenda back since she's into muscles. The guys provide him with shoulder pads concealed by a heavy jacket so he'll look muscular. Micky then confronts Brenda on the beach despite having trouble walking but the Bulk shows up figuring out the truth and overpowers Micky once again where he once again lands near Shah-Ku who finally manages to convince to join Weakling Anonymous.
Following Shah-Ku's example, Micky fasts for two days to purify his tissues so much so that he keels over from hunger, worrying his mates. Peter puts through a call to Shah-Ku to voice his concerns over Micky's condition: Shah-Ku suggests he use green rice to fix him up. Then Shah-Ku tells Bulk of his devious plans of getting Micky to hock his drums as soon as he picks him up that night. At dinner, Micky has thrown out all the meat and instead makes them a meal of fried fermented goat milk curd burned in a dash of lemonseed oil to a crisp, golden green (yum!), and some scraped mountain moss au gratin (plain lettuce) with a special peanut shell base. Shah-Ku enters The Monkees' pad, views its surroundings and its inhabitants with extreme distaste, and takes hunger-weak Micky to the gym for a meeting with WA. Not long after, Peter returns to the pad and claims to David he has seen Shah-Ku at a hot dog stand, making then suspicious that Shah-Ku is a fake! At the Weakling Anonymous meeting, Shah-Ku gives a speech to a group of weaklings as he tries to persuade Micky to sign a contract but Micky is still hesitant. Meanwhile, David and Peter arrive at the meeting and don WA sweat suits in order to disguise themselves as members and blend with the surroundings. When Shah-Ku asks for people to give a speech expressing how WA has affected their lives, both David and Peter take turns protesting the ill effects on Micky by giving false stories in order to discredit the club, and Shah-Ku orders his heavies to work them over. Soon chaos erupts as David rams into Shah-Ku, who doubles up in pain, exposing him as a fake to The Weaklings and when Bulk enters the room, Micky realizes he was a mere shill for Shah-Ku. In the chase set to "Sunny Girlfriend" that follows, the superhero-clad Monkeemen and the "Weaklings" get the best of Shah-Ku and his cronies.
Later at the beach, Micky is united with Brenda again, when a scrawny intellectual with his nose buried in a book, kicks sand in his face. As Micky prepares to attack him, Brenda, attracted to a man with a mind, walks off with the bookworm, leaving Micky pouting. Michael joins the trio in as they conclude the show with a musical number: "Love Is Only Sleeping."