Mickey has just remembered that it's Valentine's day. Here kids learn that fictional anthropomorphised cartoon mice suffer the same stereotypes as human men in that they are always unprepared for romantic holidays.
Mickey doesn't know what to get Minnie. This is probably because he doesn't really pay much attention to her and takes their relationship purely for granted since she's the only female fictional mouse of his acquaintance and while he fancies Daisy more, interspecies romance is apparently considered taboo in the clubhouse. He's obviously just coasting through this relationship.
Luckily a "stranger" appears at the door and offers to assist him with finding the perfect gift. (Is it just me or does this look like something else? Like maybe Mickey's thinking he might see a whole other side of sweet innocent Minnie? Hmmm.)
However, to set the correct expectations, and perhaps because he's slightly daft, she employs the use of visual aids.
"Knit that fine rodent a hat, man!" And so Mickey proceeds to locate a sheep, sheer it, spin the wool into yarn, and dye it. Thereby educating the youth of today on the wonders of the fiber arts and that a seemingly straight male can find enjoyment in making his own yarn.
The mysterious stranger even provides the knitting needles, though honestly they seem a rather small size for the weight of that yarn, but it is fiction so I'll let it slide.
And wouldn't you know it, Mickey is able to create the perfect gift for Minnie, therein bringing home the most important message of all to young girls.
Girls, if you want that perfect gift, you're better off just getting it for yourself. That is unless you enjoy wearing trench coats (and then having to make it clear, that no, you are not there to role play as a stripper), drawing pictures of exactly what you want and supplying all the tools for him to make/get it for you.
Happy Valentine's Day all! Go out and get yourselves something nice.