>>5875909>>5875911Summary for this came up on the wiki:
In 2021, the Autobot Second Army has activated the transtector factory in G Nebula 89, and though they're routing all their energy into the factory's operations and thus run the risk of being unable to defend it, Grand Maximus insists that they must do their part of the plan to resurrect Optimus Prime on Cybertron. His own contribution is to implement the "Super Convoy Project", a plan to recreate the transtector that was meant for Prime but turned into Ginrai, but first he must find shelter for Cancer, Bullhorn, Wilder, and Clouder, who've smuggled themselves into the base in search of new transtectors following their final battle.
With the base under siege by Overlord's troops and the space bridge network broken, Grand believes the only place where the humans can be safe is in the Legends Universe, and coordinates the opening of a portal with Fortress (who is less than enthused to receive the humans, but relents when his brother calls him out on getting too used to a peaceful life). Arriving in the Legends world, the former Headmaster Juniors are reunited with their Autobot counterparts, Minerva, Cab, and Shūta, who explain that they joined Fortress's crew in search of them. As an apology for making them worry, Bullhorn presents them with new Headmaster-Braces that let them turn into Headmasters again. At that moment, Shockwave appears in the Legends Universe in search of Megatron, and marks Cancer as imperative to his plan...
This explains why the Headmaster Jr's (and Clouder) are all around, setting this immediately after Masterforce. Note that while events in this comic are unfolding, so are the Lynx Master, and later the Megatronia comic (thus, why they're trying to complete "Super Convoy" to revive the Optimus on Cybertron, which will inevitably go wrong, and end with Optimus body being stolen by Dark Nova).
