Michelle,
what a great story: The Big Box, Oxford Reading Tree Level 1
https://youtu.be/GS2DHx4jcVA?si=dVzap0DQLzoVGC1u
the illustrations show clearly what happened to the box when it rained, and this is a great prompt for an inquiry.
Plenty of opportunity to ‘explore‘ what happens to a material when it gets wet, in this case in terms of structural integrity. You could link it to the paper towels of Mighty Materials and do they stay strong when they get wet.