K.C. realizes she misses Darien and goes to tell him, but he reveals he has a new girlfriend. K.C. lies and says she has a boyfriend and the two agree to go on a double date.
The Coopers prepare for Poppa Earl to visit with his new fiancé, Betty. He surprises everyone with how happy he is, but K.C. recognizes Betty from an unsolved case from 1977.
K.C. is assigned to protect a foreign diplomat at a university ceremony and must go undercover by joining the school's drumline to secure a key position next to the diplomat.
Byron waits for K.C. to respond and she says she's not K.C.. but her cousin, Cassandra. Byron suggests they all go to dinner, so K.C. breaks Bernice out of jail to play her cousin.
K.C. decides to save Ernie since it was her fault the barbecue failed. They learn the Bishops have planted listening devices and someone called the "The Mask" wants the weapons sold.