▁Go ode , ▁Cel ia ▁Im rie , ▁and ▁Anthony ▁Head . ▁It ▁cent ers ▁on ▁the ▁relationship ▁between ▁Rach el ▁( Per ab o ) ▁and ▁Lu ce ▁( He ade y ), ▁who ▁meet ▁on ▁Rach el ' s ▁wed ding ▁day . ▁ ▁The ▁film ▁takes ▁its ▁title ▁from ▁the ▁first ▁line ▁of ▁the ▁song ▁" H appy ▁T ogether ". ▁W riter ▁and ▁director ▁Parker ▁reve als ▁on ▁the ▁DVD ▁audio ▁comment ary ▁that ▁the ▁film ▁was ▁originally ▁titled ▁Click , ▁after ▁the ▁French ▁term ▁for ▁love ▁at ▁first ▁sight , ▁but ▁conflicts ▁with ▁the ▁ 2 0 0 6 ▁Adam ▁Sand ler ▁film ▁Click ▁necess itated ▁the ▁name ▁change . ▁ ▁Plot ▁The ▁film ▁opens ▁on ▁H ector ▁" He ck " ▁( M att hew ▁Go ode ) ▁and ▁Rach el ' s ▁( Pi per ▁Per ab o ) ▁wed ding ▁day ▁in ▁North ▁London , ▁England ▁which ▁Rach el ' s ▁over b ear ing ▁mother , ▁T ess , ▁( C elia ▁Im rie ), ▁is ▁in ▁charge ▁of ▁planning . ▁Rach el ' s ▁father ▁Ned ▁( An th ony ▁Head ) ▁and ▁her ▁younger ▁sister ▁Henri etta ▁( B oo ▁Jackson ) ▁" H " ▁are ▁support ive . ▁F lower ▁shop ▁owner ▁Lu ce ▁( L ena ▁He ade y ) ▁and ▁Henri etta ▁are ▁ch atting ▁with ▁H ector ▁and ▁Cooper ▁" Co op " ▁( D ar ren ▁Bo yd ). ▁Henri etta ▁take ▁an ▁immediate ▁lik ing ▁to