It's wrong to let your pets escape
Guster is at home on a hot day with his cat.
Guster wants to cool down.
Guster opens his windows that have screens on them so there is some airflow in his home.
Guster opens up his back door to let the air in and doesn't lock his cat in a room.
Guster relaxes enjoying the cool breeze from the windows and pets his cat.
Guster's cat gets out the open door and is lost never to be found again which makes Guster sad.