A scene that keeps coming back no matter how I dismiss it:
What if Xeno came to Japan instead of the other way around?
Now this idea floats in my head without a good reason for it happening, but for any reason Xeno is coming looking for Senku or maybe 💜👑 looking for Gen and arrives during the Stone Wars before Gen, Chrome, and Magma leave to deliver the radio. He's basically beelined his way there, with Stan... well, Stanley is incapable telling Xeno no, but this one's been stressful enough he thought about it for half a second while the ship was being built.
And the ship's sinking when they make radio contact.
It's hubris. Xeno knows how to make things and so does Brody, but the sea is unforgiving. A humpback whale gets irritated by their fishing net, or maybe orcas object to them trying to opportunisticly snatch some of the tuna they are hunting. Minor damage, they can take it. A bad storm dumps more water on them than their bilge pump was designed for. The shape of the boat isn't ideal and they go through metal fast patching up damage. Xeno knows to use gunmetal bronze and sacrificial zinc tabs to avoid corrosion, but boat design is not the same as dealing with aerospace engineering. He could make a little boat to skirt the coast built mostly for use on a river, but crossing an ocean with all the supply and seed stock to ensure they weren't reliant on foraging if nobody's home is different.
There are small miscalculations and while he's fine with iteration - that's the scientific process - the crew isn't holding up now that Stanley's out of his area of expertise and they don't have a strong unifying goal like getting their kidnapped leader back. These are marines, not navy seamen, they don’t have anyone like Ryusui or Ukyo with experience sailing a craft on the open ocean. They have to take the longer route because rediscovering a sunstone's use is not something they would think to do. Damage happens and Xeno seems to be having fun with recycling broken bits into solutions, but this is not like Stanley stealing the Perseus and it's plans to follow the coast. Poor morale means slacking on maintenance means a snowball of small inconveniences until they are limping toward Japan and there is one last winter storm blowing down out of Siberia. (The source of the fresh looking snow all over when Senku & co run to catch Homura while the team leave with the radio.)
Leo contacts Gen and Senku on the radio, Xeno is ecstatic. They hit a rock, just to solidify that the universe thought this was a bad idea, and the villagers paddle out to rescue and salvage what they can with the wind howling.
I have a very specific and very vivid scene in my head of Xeno with his leg under a pile of boxes that fell as the sinking ship tilted, seeing Senku for the first time when our protagonist uses a combination of Magma's muscles and some lever or pulley action to free him. Properly broken bone, should not have gone back for [probably the platinum.]
















