  We consider a simple extension of the standard model, which could give a
solution to its $CP$ issues through both the Peccei-Quinn mechanism and the
Nelson-Barr mechanism. Its low energy effective model coincides with the
scotogenic model in the leptonic sector. Although leptogenesis is known not to
work well at lower reheating temperature than $10^9$ GeV in simple seesaw and
scotogenic frameworks, such low reheating temperature could be consistent with
both neutrino mass generation and thermal leptogenesis via newly introduced
fields without referring to the resonance effect. An alternative dark matter
candidate to axion is prepared as an indispensable ingredient of the model.
