Wedding bells are ringing in Adventure 337 (Oct 65), but the Legion Constitution forbids married members, and spies from Murra plot to take advantage of that, in this Edmond Hamilton story.
Brainiac 5 has been elected as the new leader of the team, though the election is not shown or its process explained. It’s no surprise that it’s Brainiac 5, who had been touted as a possible leader in the last “election,” and lead the side against Saturn Girl when the Legion warred against itself.
The two established inter-Legion romances come to the fore, Lightning Lad and Saturn Girl, and Ultra Boy and Phantom Girl. When they announce plans to marry, they are also forced to resign from the team, but none of the four seem to mind that in the slightest.
The unusual sticks with figures of the members on them, shown both in the story and on the cover, re-appear in a story in the early 90s, in which they are called “ceremonial wedding sticks,” and their use is very formal and old-fashioned. In that story, we learn that the couple that wed get to keep the sticks, as a memento of those who were part of the wedding party.
Try-outs are held to replace the four members, and though Subs Night Girl and Chlorophyll Kid apply again, they are rejected (again) in favour of three Murran spies who have been temporarily endowed with powers, and join as Size Lad, Blackout Boy and Magnetic Kid. While there would later be a Legionnaire named Magnetic Kid, his powers would be identical to Cosmic Boy, not the abilities of this one, to draw anything or anyone towards him. Blackout Boy has basically the same shadow casting abilities that later member Shadow Lass would have,
The remainder of the story simply reveals that the weddings were a ruse to draw out these spies, the “Plan R”, for Romance, that was referred to in the first panel. Brainiac 5 neutralizes the powers of the spies, while Superboy and Mon-El destroy the machine that created the powers.
As the weddings were a sham, the four members never really had to resign, but their relationships are pretty open from this time forward. Curiously, the first Legion marriage would not be between these Legionnaires at all.