Kim has been comparing your schedules to try and see when you guys could hang out, and happened to notice the suntan lotion photo shoot in Mexico.
The thing is, she has a friend whose boyfriend she suspects may be cheating on her, and she needs your help.
She wants you to head over to the boyfriend's usual breakfast spot and flirt with him to see if he takes the bait and she'll call you after to hear the result.
Being a good friend, you agree to help her out. Although this goal is concurrent with the Sunspot Tanner goal, the outcome of goal doesn't affect that one and vice versa.
Tap the gold glasses icon to enter and tap the yellow speech bubble next to Derek Long to begin the goal.
When you start flirting with him, Derek is very receptive, and quickly invites you back to his hotel room. When you call him a cheater, he tries to backpedal and even attempts to bribe you to keep his secret.
You can choose whether or not to accept the bribe and whether to tell Kim when she calls you afterwards to ask if he accepted your advances.
Either way, at the end of the conversation, Kim hangs up, and the goal is complete.