Things boys don’t think when they are jumping into the water holding hands with a cute girl.
Panel 1:
Lynn begins what will be the only sentence in this comic strip, thought by Michael in all 4 panels. He and Martha are holding hands and preparing to jump into the water from the rail on the back of the boat. That sounds little painful on the feet.
Panel 2:
They leap together lifting their chins to the air, closing their eyes, while Michael thinks, “…The Ultimate test.” Based on the picture, it would appear the ultimate test is synchronized jumping or unusual aging. Physically Martha changes to look like she is in her 20s.
Panel 3:

For some reason Lynn Johnston has an obsession with kids going underwater and holding their nose. Both Michael and Martha hold their nose as they go in. This is for kids with no breath control under water. I kind of understood why Elizabeth did that, but I would have thought Michael and Martha were better swimmers than Elizabeth. Chee! Martha’s dad has a boat!
Panel 4:
Oh this is going to be a problem for Martha. Mike does not look good soaking wet. He looks like a character out of Hi and Lois.

Also, wet t-shirt contests are based on the idea of someone looking good soaking wet and I can assure you that love has little to do with it.
Summary:
Aside from the idiotic pronouncement that is the heart of today’s comic strip, I do like the fact that for the first time we see Michael and Martha both making love hearts at each other at the same time. It only took two years, but they finally did it.