diff --git a/implementation.go b/implementation.go
index 129e9af..84e9c7f 100644
--- a/implementation.go
+++ b/implementation.go
@@ -43,6 +43,11 @@ func (f implementation) unmarshal(prefix Key, dest interface{}) error {
 	for i := 0; i < vt.NumField(); i++ {
 		field := vt.Field(i)
 		value := v.Field(i)
+		tag := field.Tag.Get("flatpack")
+		// Skip processing the field.
+		if tag == "-" {
+			continue
+		}
 
 		name[len(name)-1] = field.Name
 		err := f.read(name, value)
@@ -149,7 +154,7 @@ func (f implementation) read(name Key, value reflect.Value) error {
 			}
 		}
 	case reflect.Struct:
-		f.unmarshal(name, value.Addr().Interface())
+		err = f.unmarshal(name, value.Addr().Interface())
 	case reflect.Ptr:
 		// Handle pointers by allocating if necessary, then recursively calling
 		// ourselves.
diff --git a/unmarshal_test.go b/unmarshal_test.go
index 68ed2e1..391af15 100644
--- a/unmarshal_test.go
+++ b/unmarshal_test.go
@@ -34,6 +34,17 @@ type exoticPerson struct {
 	Age   chan bool
 }
 
+type exoticTaggedPerson struct {
+	Email map[int]bool `flatpack:"-"`
+	Age   chan bool    `flatpack:"-"`
+	Mass  float32
+}
+type nestedExoticPerson struct {
+	Family struct {
+		Father map[string]bool
+	}
+}
+
 // For testing Validater callbacks
 type dysfunctionalPerson struct {
 	person
@@ -105,6 +116,14 @@ var _ = Describe("Unmarshal()", func() {
 			Expect(Unmarshal(&got2)).To(MatchError("invalid value: cannot parse string as float (value=carol@example.com,error=invalid syntax)"))
 			got3 := exoticPerson{}
 			Expect(Unmarshal(&got3)).To(MatchError("invalid type: unsupported data type (key=Email,type=map[int]bool)"))
+			got4 := nestedExoticPerson{}
+			Expect(Unmarshal(&got4)).To(MatchError("invalid type: unsupported data type (key=Family.Father,type=map[string]bool)"))
+		})
+
+		It("skips the fields marked with flatpack tags", func() {
+			got := exoticTaggedPerson{}
+			Expect(Unmarshal(&got)).To(BeNil())
+			Expect(got.Mass).To(Equal(float32(16.84)))
 		})
 	})
 })