  We study numerically and analytically the dynamical (AC) conductance through
a two-dot system, where only one of the dots is coupled to the leads but it is
also side-coupled to the other dot through an antiferromagnetic exchange (RKKY)
interaction. In this case the RKKY interaction gives rise to a ``two-stage
Kondo effect'' where the two spins are screened by two consecutive Kondo
effects. We formulate a renormalized scaling theory that captures remarkably
well the cross-over from the strongly conductive correlated regime to the low
temperature low conductance state. Our analytical formulas agree well with our
numerical renormalization group results. The frequency dependent current noise
spectrum is also discussed.
