The Avengers (vol 1) #188 VF

"Elementary, Dear Avengers!" Plot by Jim Shooter. Script by Bill Mantlo. Art by John Byrne (breakdowns), Dan Green (finishes), and Frank Springer (finishes). Cover by John Byrne and Terry Austin. After finishing their epic adventure against Chthon last issue, Earth's Mightiest Heroes stop by the Great Refuge to drop off Quicksilver. Since the next leg of their journey will pass over the Soviet Union, the shield-slinger contacts a nearby MiG fighter to request authorization to navigate Russian airspace. But while Cap is conversing with the pilot, the MiG suddenly explodes! How did that happen? The Avengers decide to investigate and land at a Soviet nuclear power plant...without permission! Is this the end of détente? However, the red army is not the enemy! It's the periodic table! Seven avengers go to school against Carbon, Phosphorus, Chlorine, Radium, and Vanadium! Cameo appearances by Crystal, Black Bolt, Gorgon, Karnak, and the Darkhold. Avengers Lineup: Beast, Captain America, Falcon, Ms. Marvel, Scarlet Witch, the Wasp, and Wonder Man. (Notes: In this issue Crystal reveals that she is pregnant. Her baby, Luna, is born in Fantastic Four 240. The Elements of Doom return many years later in Thunderbolts 6.) Cover price $0.40.