2 homosapiens ascended a certain geological protuberance to collect a hydride of oxygen who’s quantity isn’t specified.
1 member descends dramatically suffering mechanical damage to the cranial part of his anatomical structure. The 2nd member follows the first in a similar series of rapid irregular disturbing movements.

In simple English:
Jack & Jill went up the hill to fetch a pail of water.
Jack fell down and broke his crown and Jill came tumbling after.