invisible ink siphoned through one last straw

Let’s say that whilom, two people were sitting in a room. We’ll call them Alice and Bob. A third person—Carlita, or perhaps Eve—sat in the next room and appeared to read.

Bob spent the afternoon working on his laptop. Alice and Carlita had gone out that day. Alice tried to describe the outing upon their return and ran out of words. Alice resorted to a short nap. After the nap, she started to show Bob the walking route on a map.

Bob said, “This story wasn’t very entertaining the first time.”

During the outing, Alice and Carlita had taken a fourth person—let’s call him Dave—for a short walk. Dave nearly fell twice upon short Carlita. For the walk’s second half Alice all but carried Dave, arm across shoulder, including a long pause to rest when Dave could barely stand.

What happened next?