ichidan verb
be on the verge of; be about to; be close to
Used with the continuative form (連用形) of a verb to indicate that an action or state is about to happen or is almost reached. Often implies a process that is nearly complete.
彼は医者になりかけている。
He is on the verge of becoming a doctor.
空が
The sky was starting to turn the color of sunset.
計画は白紙になりかけた。
The plan nearly came to nothing.