▁vac ation ▁time ▁he ▁has ▁accum ulated . ▁At ▁first ▁Mac ▁is ▁uncertain ▁if ▁he ▁wants ▁to ▁go , ▁but ▁after ▁the ▁events ▁in ▁the ▁episode ▁take ▁place , ▁he ▁inform s ▁his ▁team m ates ▁that ▁he ▁is ▁going ▁to ▁England ▁with ▁P ey ton . ▁However , ▁Mac ▁returns ▁to ▁New ▁York ▁without ▁P ey ton ▁at ▁the ▁start ▁of ▁season ▁ 4 , ▁and ▁at ▁the ▁end ▁of ▁the ▁ 4 th ▁episode , ▁" Time ' s ▁Up ", ▁he ▁receives ▁a ▁letter ▁from ▁her ▁saying ▁that ▁she ▁has ▁decided ▁to ▁stay ▁in ▁London ▁with ▁her ▁family ▁and ▁that ▁a ▁long - distance ▁relationship ▁would ▁never ▁work , ▁because ▁" how ever ▁close ▁we ▁may ▁be , ▁there ▁would ▁always ▁be ▁an ▁ocean ▁between ▁us ." ▁Mac ▁see ks ▁sol ace ▁in ▁his ▁bass ▁guitar ▁in ▁a ▁jazz ▁bar . ▁ ▁Mac ' s ▁relationship ▁with ▁former ▁M . E . ▁and ▁junior ▁C SI ▁Sh eld on ▁Haw kes ▁is ▁am ic able ▁for ▁the ▁first ▁two ▁seasons . ▁However , ▁in ▁episode ▁ 3 . 0 7 ▁" M ur der ▁S ings ▁the ▁Blues ", ▁Haw kes ▁tries ▁to ▁make ▁sure ▁he ▁stays ▁on ▁a ▁case ▁by ▁not ▁inform ing ▁Mac ▁of ▁his ▁relationship ▁to ▁the ▁victim ▁in ▁one ▁of ▁their ▁cases ; ▁however , ▁Mac ▁feels ▁bet rayed ▁when ▁P ey ton ▁in ad vert ently ▁reve als ▁Haw kes ' ▁secret , ▁and ▁Mac ▁dress es ▁him ▁down ▁in ▁front ▁of ▁the ▁entire ▁lab