Drone - Prone
Prone - Crone
Crone - clone
Clone - anole
anole - lance
Lance - dance
dance - crane
Crane - grace
Grace - Cargo
Cargo - Argon
Argon - Goner
Goner - Grope
Grope - Group
group - proud
Proud - pound
pound - mound
Mound - Round
Round - sound
sound - donut
donut - doubt
Doubt - about
about - boast
Boast - boost
Boost - Roots
roots - store