秘計 is read as ひけい (hikei) and means secret plan.
ひけい
hikei
ひみつけいさん
secure computation
ひしょ
(private) secretary
ひみつ
esoteric teachings
ひめる
to hide
ひぞう
treasuring
ひわ
secret story
ひきょう
unexplored region
ひさく
secret plan
ひでん
secret (recipe, medicine, etc.)
ひとく
hiding
ひしょきょうかい
Chartered Institute of Secretaries
ひしょけんてい
official test for a secretarial qualification