The Arnold Schwarzenegger Netflix spy comedy “Fubar” starts out so unfettered by reality that it holds real promise.

Luke Brunner, the CIA operative played by Schwarzenegger, who is 75, is described as being 65. He is on the eve of retirement when they pull him back in to infiltrate the Guyana compound of arms dealer Boro (Gabriel Luna), a guy so brutal that he kills an associate on stage at an outdoor party and orders the blood-splattered band to keep playing.

Also in Guyana is Luke’s do-gooder daughter, Emma. Unbeknownst to her father, she is also a CIA operative and so deeply embedded in Boro’s world that she has become his favorite fight-club competitor.

Monica Barbaro and Arnold Schwarzenegger in “Fubar.” (Christos Kalohoridis/Netflix)

Worse yet, horrified patriarch Luke discovers that Emma smokes, drinks and uses curse words, when he thought he had raised a lady. Emma, who always found...