NDSolve解完方程后，无法画出函数图像(代码如下)

Question

intrinsic[f_, a_ : 0, {c_ : 0, d_ : 0, e_ : 0}, {min : -10, max : 10},

     opts_][t_] :=

  Module[{x, y, \[Theta], s},

   eqic = {x'[s] == Cos[\[Theta][s]],

     y'[s] == Sin[\[Theta][s]], \[Theta]'[s] == f[s], x[a] == c,

     y[a] == c, y[a] == d, \[Theta][a] == e};

   sol = NDSolve[eqic, {x, y, \[Theta]}, {s, min, max}, opts];

   {x[t], y[t]} /. sol

   ];

f[s_] := s/(s + 1);

\[Alpha][t_] := intrinsic[f, 0, {0, 0, 0}, {0, 20}]

ParametricPlot[Evaluate[\[Alpha][t]], {t, 0, 20}]